Page 26 - 2014 Printable Abstract Book
P. 26
PRESIDENTIAL SYMPOSIUM
The major health and medical issues astronauts face during and following spaceflight will be
discussed with an emphasis on space radiation effects. Contributions from space radiobiology research in
estimating cancer and central nervous system risks are reviewed and new results described.
(Pres 101) Human Health and Performance Risk Management for Space Exploration. Jeffrey R. Davis,
MD, NASA Johnson Space Center, Houston, TX
The Human Health and Performance Directorate (HH&P) provides the research and technology
development required for exploration as well as all human health and performance support to space flight
operations of International Space Station, commercial space flight, space technology development, and
planning for deep space exploration to Mars and other destinations. This presentation will review
spaceflight challenges to astronaut health, including those in space medicine; biomedical research and
countermeasures for the physiological changes induced by human exposure to reduced gravity; and the
unique environmental challenges of spaceflight such as space radiation. NASA’s approach to risk
evaluation and mitigation will be described and examples of the 32 human health and performance risks
under management will be provided. New and innovative approaches to overcome the obstacles of
spaceflight risks will also be described.
(Pres 102) The Biological Basis of Radiation Carcinogenesis in Epithelial Tissues. Mary Helen. Barcellos-
Hoff, NYU School of Medicine, New York, NY
Clear mechanistic understanding of the biological processes elicited by high LET radiation that
increase cancer risk will reduce the uncertainties in assessing the risk of space flight. Radiation is capable
of both initiating and promoting carcinogenesis due, respectively, to the consequences of DNA damage
and altered signaling, phenotype and multicellular interactions. It is unknown the relative contribution of
each to the greater carcinogenic potential of high LET radiation. To examine this question, we used a
mammary chimera mouse model to separate radiation effects acting on the epithelium versus those that
act via tissue interactions and signaling in the host. The inguinal mammary glands of wild type Balb/c host
mice were cleared of endogenous epithelium and transplanted with oncogenically primed Trp53 null
syngeneic mammary fragments. One group was irradiated before transplantation (i.e. epithelium was not
exposed) and the other group was irradiated after Trp53 null outgrowth were established (i.e. epithelium
was exposed). Mice irradiated with densely ionizing charged particles or sparsely ionizing γ-ray radiation
were compared to contemporaneous sham-irradiated controls. Notably, whether the Trp53 null
mammary outgrowths were irradiated or not, the tumors arising in mice exposed to high or low LET
radiation were more aggressive based on behavior, markers and genomic profiling than tumors arising in
non-irradiated mice. These qualitative effects were more pronounced in high LET irradiated hosts.
Together these data suggest that radiation induced tissue interactions promote more aggressive cancers
and that high LET may be more effective than low LET radiation. This research was supported by NASA
Specialized Center for Research in Radiation Health Effects, NNX09AM52G.
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The major health and medical issues astronauts face during and following spaceflight will be
discussed with an emphasis on space radiation effects. Contributions from space radiobiology research in
estimating cancer and central nervous system risks are reviewed and new results described.
(Pres 101) Human Health and Performance Risk Management for Space Exploration. Jeffrey R. Davis,
MD, NASA Johnson Space Center, Houston, TX
The Human Health and Performance Directorate (HH&P) provides the research and technology
development required for exploration as well as all human health and performance support to space flight
operations of International Space Station, commercial space flight, space technology development, and
planning for deep space exploration to Mars and other destinations. This presentation will review
spaceflight challenges to astronaut health, including those in space medicine; biomedical research and
countermeasures for the physiological changes induced by human exposure to reduced gravity; and the
unique environmental challenges of spaceflight such as space radiation. NASA’s approach to risk
evaluation and mitigation will be described and examples of the 32 human health and performance risks
under management will be provided. New and innovative approaches to overcome the obstacles of
spaceflight risks will also be described.
(Pres 102) The Biological Basis of Radiation Carcinogenesis in Epithelial Tissues. Mary Helen. Barcellos-
Hoff, NYU School of Medicine, New York, NY
Clear mechanistic understanding of the biological processes elicited by high LET radiation that
increase cancer risk will reduce the uncertainties in assessing the risk of space flight. Radiation is capable
of both initiating and promoting carcinogenesis due, respectively, to the consequences of DNA damage
and altered signaling, phenotype and multicellular interactions. It is unknown the relative contribution of
each to the greater carcinogenic potential of high LET radiation. To examine this question, we used a
mammary chimera mouse model to separate radiation effects acting on the epithelium versus those that
act via tissue interactions and signaling in the host. The inguinal mammary glands of wild type Balb/c host
mice were cleared of endogenous epithelium and transplanted with oncogenically primed Trp53 null
syngeneic mammary fragments. One group was irradiated before transplantation (i.e. epithelium was not
exposed) and the other group was irradiated after Trp53 null outgrowth were established (i.e. epithelium
was exposed). Mice irradiated with densely ionizing charged particles or sparsely ionizing γ-ray radiation
were compared to contemporaneous sham-irradiated controls. Notably, whether the Trp53 null
mammary outgrowths were irradiated or not, the tumors arising in mice exposed to high or low LET
radiation were more aggressive based on behavior, markers and genomic profiling than tumors arising in
non-irradiated mice. These qualitative effects were more pronounced in high LET irradiated hosts.
Together these data suggest that radiation induced tissue interactions promote more aggressive cancers
and that high LET may be more effective than low LET radiation. This research was supported by NASA
Specialized Center for Research in Radiation Health Effects, NNX09AM52G.
24 | P a g e
