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Stephanie Suzanne Krieger

Publications and source records attributed to Stephanie Suzanne Krieger.

Chimeric Mouse Models for Space Radiation Risk Investigations

Assessment of human health risks associated with space radiation exposure is based largely on the knowledge learned from studies in which animals, mostly rodents, are exposed to high-LET radiation on the ground. It has been recognized that translation of animal results to meaningful implications for human disease can be challenging, particularly for certain risk categories such as the high-LET radiation effects in the central nervous system (CNS). Considering limitations in utilizing non-human primates and clinical studies in humans, chimeric animals can potentially bridge the knowledge gap between rodents and humans. In a chimeric animal, a specific organ or a cell type is replaced with respective human cells that are functional. A number of chimeric mouse models have been developed in the medical research community to study human diseases, and some of the models can potentially be used for NASA applications. Here we investigate use of mice engrafted with human hepatocytes, which have been used in studies of genotoxicity from carcinogen exposures, for assessment of space radiation damage. In a pilot study, we use PXB mice whose livers contain >90% human cells and have been found to function nearly identically to human liver tissues. These mice were exposed to gamma rays for investigations of DNA damage, transcriptomics, and histopathological changes in the humanized livers. Results obtained from PXB mice were compared non-engrafted control animals from the same background strain that are exposed to identical conditions. Preliminary data from histopathological analysis suggest chimeric mouse models are suitable for investigations of space radiation risks, as the humanized liver tissue exhibited changes induced by radiation and was markedly distinct from the liver tissue from the control animals (Fox Chase SCID mice).

Radiation effects↗

Research Operations and Integration Flight Session – Always Sweat the Small Stuff

Human research routinely involves elaborate operations with substantial hardware setup, such as functional MRIs, CT scans, ultrasounds, exercise sessions, and cardiac evaluations. These conspicuous operations garner most of our attention and, understandably, resources, but the unsung heroes of spaceflight human research often get by with little fanfare. The collection of human samples and surveys is often just as much of a challenge in terms of both planning and logistics. The samples and surveys are often collected or completed by the crew autonomously, with little to no oversight from science support staff, which puts them the most at risk for data loss. The Research Operations and Integration team will host an interactive session with audience participation to demonstrate the importance of the written communications and instructions that are provided to the astronauts. During this hands-on session, ROI will walk through the challenges faced to ensure astronaut subjects can successfully collect all the various samples (e.g., saliva, fecal, urine, and blood) that the human research community needs. The format will be part lecture and part game show intended to provide both an enlightening and fun session. As we often instruct the crew: “Don’t forget to arrive fasted and bring a list of all the medications you’ve taken in the past week.”

Cherie Morgan Oubre↗