Page 165 - 2014 Printable Abstract Book
P. 165
significant degree of body weight. Body composition analysis revealed that this occurred from both fat
and lean mass compartments. Critically, this was accompanied by molecular evidence of ubiquitin
proteasome system activation in skeletal muscle. Conclusions: These results demonstrate that localized
radiation therapy is capable of inducing the behavioral and metabolic features of cachexia, likely via the
induction of circulating inflammatory cytokines. This introduces the possibility of the simultaneous
delivery of radiation therapy with one of many anti-catabolic agents currently under development.
1
(PS2-51) A mouse ear model for microbeam-induced bystander effects in vivo. Manuela Buonanno ;
2
1
1
2
2
Gerhard Randers-Pehrson ; Lubomir Smilenov ; Norman J. Kleiman ; Erik Young ; and David J. Brenner
Columbia University, RARAF, New York, NY and Columbia University, CRR, New York, NY
1
2
Microbeams have been fundamental to investigate radiation-induced bystander effects in cell
cultures and 3D systems. The next logical step is to implement microbeam irradiation protocols to study
effects in living organisms. To this end, we have developed a mouse ear model for bystander studies. With
an average thickness of 250-300 µm, this model can be used to investigate radiation-induced bystander
effects with the Columbia 3-MeV proton microbeam (LET 12.5 keV/µm) whose range is 134 µm. In our
current protocol, the ear of anesthetized mouse is flattened onto the underside of a flat plate of a custom-
made holder using gentle suction; the flattened mouse ear is then placed over the micro-beam port and
cells along a line of the ear are irradiated with the proton microbeam with a selected diameter. At chosen
times after irradiation, mice are sacrificed and a punch of the ear is collected. Tissues are then fixed,
paraffin-embedded and cut in 5-µm sections perpendicularly to the direction of the charged particle
beam. The sections are then analyzed for biological endpoints (i.e. formation of repair protein foci,
apoptosis) as a function of the distance from the irradiated line. Using γH2AX foci formation as endpoint
assessed by immunohistochemical analysis, we found that compared to control proton irradiation induced
γH2AX foci formation in ears of C57BL/6 mice. On microscopic cross section, the ear of a mouse consists
of two full-thickness layers of skin separated by a thin supporting skeleton of elastic cartilage: as expected,
γH2AX foci-positive keratinocytes were observed only in one of the two epidermal layers of the ear. Cells
adjacent or in the epidermal layer opposite to the γH2AX positive region did not exhibit foci. Strikingly,
assuming that mouse keratinocytes are 9-11 µm in diameter, a higher number of cells than expected
showed foci. In a particular experiment, although the proton irradiated line was ~ 35 µm wide, the average
length spanned by γH2AX positive cells exceeded 150 µm. These results suggest that microbeam proton
irradiation induced DNA damage in bystander cells in vivo. Ongoing experiments aim at investigating the
kinetics of DNA repair foci formation in microbeam irradiated ears as well as the molecular mechanisms
involved.
(PS2-53) Mechanisms contributing to the sequelae of the prolonged GI syndrome in mice. Terez Shea-
1
1
2
1
1
1
Donohue, PhD ; Greg Tudor, BS ; Aiping Zhao, MD ; Neemesh Desai, BS ; Rex Sun, BS ; Leon McLean, MD ;
2
1
1
Alexander Bennett, BS ; Ann Farese, M.S. ; Catherine Booth, PhD ; and Thomas MacVittie, PhD
1
2
University of Maryland School of Medicine, Baltimore, MD and Epistem, Manchester, United Kingdom
1
The new reality model using partial body irradiation with 5% bone marrow shielding (PBI/BM5)
allows investigation of the delayed effects of acute radiation exposure. Control of gut mucosal barrier
function is critical to limiting passage of material that may trigger inflammation. Intestinal stem cells are
163 | P a g e
and lean mass compartments. Critically, this was accompanied by molecular evidence of ubiquitin
proteasome system activation in skeletal muscle. Conclusions: These results demonstrate that localized
radiation therapy is capable of inducing the behavioral and metabolic features of cachexia, likely via the
induction of circulating inflammatory cytokines. This introduces the possibility of the simultaneous
delivery of radiation therapy with one of many anti-catabolic agents currently under development.
1
(PS2-51) A mouse ear model for microbeam-induced bystander effects in vivo. Manuela Buonanno ;
2
1
1
2
2
Gerhard Randers-Pehrson ; Lubomir Smilenov ; Norman J. Kleiman ; Erik Young ; and David J. Brenner
Columbia University, RARAF, New York, NY and Columbia University, CRR, New York, NY
1
2
Microbeams have been fundamental to investigate radiation-induced bystander effects in cell
cultures and 3D systems. The next logical step is to implement microbeam irradiation protocols to study
effects in living organisms. To this end, we have developed a mouse ear model for bystander studies. With
an average thickness of 250-300 µm, this model can be used to investigate radiation-induced bystander
effects with the Columbia 3-MeV proton microbeam (LET 12.5 keV/µm) whose range is 134 µm. In our
current protocol, the ear of anesthetized mouse is flattened onto the underside of a flat plate of a custom-
made holder using gentle suction; the flattened mouse ear is then placed over the micro-beam port and
cells along a line of the ear are irradiated with the proton microbeam with a selected diameter. At chosen
times after irradiation, mice are sacrificed and a punch of the ear is collected. Tissues are then fixed,
paraffin-embedded and cut in 5-µm sections perpendicularly to the direction of the charged particle
beam. The sections are then analyzed for biological endpoints (i.e. formation of repair protein foci,
apoptosis) as a function of the distance from the irradiated line. Using γH2AX foci formation as endpoint
assessed by immunohistochemical analysis, we found that compared to control proton irradiation induced
γH2AX foci formation in ears of C57BL/6 mice. On microscopic cross section, the ear of a mouse consists
of two full-thickness layers of skin separated by a thin supporting skeleton of elastic cartilage: as expected,
γH2AX foci-positive keratinocytes were observed only in one of the two epidermal layers of the ear. Cells
adjacent or in the epidermal layer opposite to the γH2AX positive region did not exhibit foci. Strikingly,
assuming that mouse keratinocytes are 9-11 µm in diameter, a higher number of cells than expected
showed foci. In a particular experiment, although the proton irradiated line was ~ 35 µm wide, the average
length spanned by γH2AX positive cells exceeded 150 µm. These results suggest that microbeam proton
irradiation induced DNA damage in bystander cells in vivo. Ongoing experiments aim at investigating the
kinetics of DNA repair foci formation in microbeam irradiated ears as well as the molecular mechanisms
involved.
(PS2-53) Mechanisms contributing to the sequelae of the prolonged GI syndrome in mice. Terez Shea-
1
1
2
1
1
1
Donohue, PhD ; Greg Tudor, BS ; Aiping Zhao, MD ; Neemesh Desai, BS ; Rex Sun, BS ; Leon McLean, MD ;
2
1
1
Alexander Bennett, BS ; Ann Farese, M.S. ; Catherine Booth, PhD ; and Thomas MacVittie, PhD
1
2
University of Maryland School of Medicine, Baltimore, MD and Epistem, Manchester, United Kingdom
1
The new reality model using partial body irradiation with 5% bone marrow shielding (PBI/BM5)
allows investigation of the delayed effects of acute radiation exposure. Control of gut mucosal barrier
function is critical to limiting passage of material that may trigger inflammation. Intestinal stem cells are
163 | P a g e
