ESTRO 2023 - Abstract Book

S58

Saturday 13 May

ESTRO 2023

Results We consistently generated perfusable microvascular networks on a chip (Figure 1 and 2). Their morphological evaluation showed an average vessel length of 128.5 ± 21.9 µ m, a length density equal to 7.0 ± 1.7 mm/mm2, an average diameter of 80.8 ± 10.1 µm, and junctions’ density equal to 34.9 ± 12.7 mm(-2). We demonstrated network perfusion by injecting 4 µ m diameter microspheres, with a volume comparable to red blood cells. Irradiation altered the permeability of the network to 40 kDa dextran (Figure 2). Such an alteration is dose-dependent and is recovered 24h after irradiation. DSB analysis shows a similar dose-dependent response and a DNA damage repair in time, reducing the number of γ H2AX foci at 24h as compared to 3h (figure 2).

Conclusion As far as we know, this is the first application of a perfusable microvascular network to study alterations of vessel wall permeability due to ionizing radiation. Such an advanced model enables a better reproduction of the microenvironment, leveraging 3D culture techniques to include the microvascular component. Our first analyses showed a permeability increase after photon-based irradiation. This study was funded by AIRC Investigator Grant, no. IG21479. OC-0095 Effects of X-ray Irradiation on Extracellular Vesicles Isolated from Head and Neck Cancer Cells I.S. Juvkam 1 , O. Zlygosteva 2 , M. Sitarz 3 , E. Malinen 4,5 , N. Edin 2 , H. Galtung 1 , T. Søland 1,6 1 University of Oslo, Institute of Oral Biology, Oslo, Norway; 2 University of Oslo, Department of Physics, Oslo, Norway; 3 Aarhus University Hospital , Danish Center for Particle Therapy, Aarhus, Denmark; 4 University of Oslo , Department of Physics, Oslo, Norway; 5 Oslo University Hospital, Department of Medical Physics, Oslo, Norway; 6 Oslo University Hospital, Department of Pathology, Oslo, Norway Purpose or Objective Extracellular vesicles (EVs) are membrane-bound vesicles released from cells through different biogenesis pathways. EVs contain nucleic acids, lipids and proteins from the releasing cell that can be taken up by recipient cells and alter their function. Thus, EVs are important in cellular communication in physiological and pathological processes and can be used as potential biomarkers in diseases such as cancer. Ionizing radiation used in cancer therapy causes direct damages to the