S2568
Radiobiology – Normal tissue radiobiology
ESTRO 2026
validate the in vitro findings, whole-thorax irradiations (18 Gy) were performed in preclinical mouse models (C57BL/6J). Four endpoints (7 days; 1-, 3-, and 6- months post-irradiation) were assessed by performing µCT scans, histological analysis, and a spectral flow cytometry panel targeting specifically lung endothelial cells was also realised. Results: Data analysis was performed using mathematical and bioinformatics dimensionality reduction tools, including Uniform Manifold Approximation and Projection (UMAP) and fate analysis. This approach allowed simultaneous visualization of all measured parameters, identification of marker contributions along computed phenotypic trajectories, and detection of more deleterious effects associated with increasing dose rates. Figure 1 shows the heterogeneous endothelial responses observed in vitro 7 days after 6 MV irradiation at 2.50 Gy/min. Moreover, weight was monitored weekly until the 6-month endpoint. Conclusion: Our approach provides a robust framework for assessing endothelial response heterogeneity to different irradiation modalities. It can also be adapted to other cell types or experimental conditions to investigate heterogeneous responses following therapeutic or environmental radiation exposure. References: 1 Puck and Marcus (1956). J Exp Med, 1956. 103(5): p. 653-66.2 Valentin et al., (2003). Ann ICRP. 2003;33(4):1- 117.3 Mintet et al., (2015). Am J Pathol, 2015. 185(9): p. 2550-62.4 Ben Kacem et al., (2022). Int J Radiat Biol. 2022;98(1):50-59.5 Benadjaoud et al., (2022). Int J Radiat Oncol Biol Phys. 2022;112(4):975-985. 6 Milliat et al., (2008). Ann Cardiol Angeiol. 2008;57(3):139- 148.7 Guipaud et al., (2018). Br J Radiol. 2018;91(1089):20170762. Keywords: Dose-rate, Heterogeneity, Endothelial cells
the microbiota–KYNA–GPR35 axis as a radioprotective strategy for RIE, with direct relevance to clinical radiotherapy. Keywords: Radiation-induced enteropathy, gut microbiota, ISC Digital Poster 2082 Dose-rate variations of 6MV X-rays modulate endothelial cell response heterogeneity Thomas Beck 1 , Mohamed Amine Benadjaoud 2 , Morgane Dos Santos 2 , Karen Chaaya 2 , Valérie Buard 1 , Agnès François 1 , Olivier Guipaud 1 , Fabien Milliat 1 , Vincent Paget 1 1 PSE-SANTE/SERAMED/LRMED, Autorité de sûreté nucléaire et de radioprotection (ASNR), Fontenay-aux- Roses, France. 2 PSE-SANTE/SERAMED/LRACC, Autorité de sûreté nucléaire et de radioprotection (ASNR), Fontenay-aux-Roses, France Purpose/Objective: Among the various curative approaches currently available in oncology, radiotherapy is involved in approximately 50 % of cancer treatments and is often combined with surgery, chemotherapy or immunotherapy. Recent technological advances in medical linear accelerators (LINACs) have significantly enhanced treatment precision, reducing the volume of healthy tissue exposed to radiation while maintaining antitumor efficacy. However, these innovative LINACs operate at higher energies and dose rates, the long- term effects on normal tissues remain poorly understood. In radiation biology, the relative biological effectiveness (RBE) is commonly used to compare the biological impact of a radiation beam to that of a reference. Traditionally determined through clonogenic survival assays, this result alone is insufficient to predict the fate and phenotype of irradiated cells1. Regardless of beam parameters, the photon RBE is generally assumed to be 1 (iso-effect)2, multiple studies have demonstrated that ionizing radiation (IR) induces heterogeneous phenotypic alterations that contribute to radiation-induced tissue injury3-5. Among these, endothelial dysfunction plays a central role in initiating and sustaining radiation- induced tissue damage6,7. Material/Methods: Confluent monolayers of Human Umbilical Vein Endothelial Cells (HUVECs) were irradiated (0-20 Gy) using a linear accelerator at three different dose rates (0.63, 2.50, and 5.00 Gy/min, 6 MV). Endothelial cells (ECs) were selected due to their key role in radiation- induced damage to healthy tissues. To accurately predict the adverse effects on normal tissues, we simultaneously measured 14 cellular parameters using spectral flow cytometry seven days post-irradiation. To
Digital Poster 2115
Proof-of-Concept Study on Monitoring Radiation- Induced Side Effects in Chicken Embryos with High- resolution MRI Serena Monti 1 , Annachiara Sarnella 1 , Cristina Terlizzi 1 , Luca Licenziato 1 , Ylenia Ferrara 1 , Anna Prinster 1 , Sandra Albanese 1 , Mauro Buono 2 , Caterina Oliviero 2 , Lucianna Maruccio 3 , Luca Borrelli 3 , Tommaso
Made with FlippingBook - Share PDF online