ESTRO 2024 - Abstract Book

S5244 ESTRO 2024 tissue injury, with significantly stronger septal thickening than in CO-treated mice, with repercussion in the pleural side and right lung, absent in CO-treated mice. MicroCT images analyses revealed reduced opacification and poorly-aerated volumes (<-435 HU, Hounsfield Unit) confirming the diffuse nature of the tissue damage generated in NA-treated animals compared to CO-treated ones and highlighting the limits of microCT images analyses in cases of lung inflammation. Interestingly, irradiation of animals 14 days post-NA injection, when club cells repopulation occurred, erased the differences in tissue damage observed, suggesting that club cells repopulation is done with fully-functionnal cells. Radiobiology - Normal tissue radiobiology

Conclusion:

Although further data are needed to draw definitive conclusions, first results suggest that the absence of club cells at the time of radiation exposure is deleterious in our model. Regeneration processes after NA transient depletion produce club cells that are effective in terms of epithelial protection. This project will be pursued by single cell RNA sequencing analyses on irradiated lung tissues in NA and CO-treated C57Bl6/J (fibrosis prone) and C3H (pneumonitis-prone) mice, both after transient and maintained club cells depletion via repeated NA injections. It will provide innovative and original information on the response of bronchoalveolar epithelium in an irradiation model close to clinical conditions. Although some studies remain controversial, the scientific community is taking a strong interest in the physiology of club cells, due to their stemness potential and their regenerative capacities of the bronchiolar epithelium, but also because of the UGB they synthesize, making them a target for a new therapeutic possibility for radiation-induced lung lesions.

Keywords:

Stereotactic

irradiation,

club

cells,

fibrosis

References:

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Mini-Oral

Proton minibeam radiation therapy is a promising approach for re-irradiations