Despite progress in planning and delivery of radiation therapy, treatment of abdominal tumors is dose-limited by the risk of intestinal toxicity (radiation enteropathy). The previous notion that radiation enteropathy develops exclusively as a result of crypt cell death has been supplanted. Instead, it is now widely recognized that many functional and secondary changes contribute to the manifestations of radiation enteropathy. These changes are promising targets for interventions to prevent and/or reduce radiation-induced bowel toxicity. In the intestine, there are important connections between the nervous system and cells of the immune system. Notably, sensory nerves and resident mast cells in the bowel mucosa constitute a functional unit that regulates many physiological and pathological processes through bidirectional interactions. We have shown that crosstalk between intestinal sensory nerves and mast cells substantially regulate the development of radiation enteropathy. The extension of this MERIT award will use validated genetic and phannacologic approaches, coupled with quantitative structural and functional endpoints and molecular methods, to systematically "dissect" the mechanisms by which these neuroimmune interactions modulate the intestinal radiation response. We will 1) examine the role ofthe endocannabinoid system and its relationship to mast cells and sensory neurons in early and delayed radiation enteropathy;2) determine to what extent the kinin- kallikrein system regulates radiation enteropathy development and whether the effects depend on resident mast cells or sensory nerves;and 3) investigate the significance of the sympathetic nervous system in radiation enteropathy. These experiments are based on data generated during the previous funding period and will provide substantial new insight into the basic pathogenesis of the intestinal radiation response. Advancing the understanding ofthe basic mechanisms underlying radiation enteropathy is critical for identifying targets for intervention. This research will thus facilitate development of specific strategies to minimize intestinal radiation toxicity in the clinic and thereby make radiation therapy safer and more effective.

Public Health Relevance

This research focuses on issues that are important to cancer survivors, specifically on making radiation therapy safer and more effective. The goal is to study how interactions between the immune system and nervous system in the bowel affect the development of radiation injury. The studies will generate new insight into how intestinal radiation injury occurs and help develop strategies to minimize such injury.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
4R37CA071382-15
Application #
8470356
Study Section
Special Emphasis Panel (NSS)
Program Officer
Wong, Rosemary S
Project Start
1997-05-01
Project End
2015-03-31
Budget Start
2013-04-01
Budget End
2015-03-31
Support Year
15
Fiscal Year
2013
Total Cost
$280,552
Indirect Cost
$90,347
Name
University of Arkansas for Medical Sciences
Department
Surgery
Type
Schools of Medicine
DUNS #
122452563
City
Little Rock
State
AR
Country
United States
Zip Code
72205
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Hauer-Jensen, Martin (2014) Toward development of interleukin-11 as a medical countermeasure for use in radiological/nuclear emergencies. Dig Dis Sci 59:1349-51
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Wu, Lixian; Shao, Lijian; Li, Manna et al. (2013) BMS-345541 sensitizes MCF-7 breast cancer cells to ionizing radiation by selective inhibition of homologous recombinational repair of DNA double-strand breaks. Radiat Res 179:160-70

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