FIG. 8.

Representative screenshots of necrotizing enterocolitis agent-based model, demonstrating intact mucus, patchy apoptosis, and necrosis. The topology of the model is a square grid. Neonatal gut epithelial cell (NGEC) agents are represented as solid circles of various shades of red: Lighter shades denote Low Stress, whereas deepening red corresponds to greater levels of stress, leading to black solid circles. Bacterial agents are rod-shaped: Green if non-adherent, green outline with red cores if adherent and activated. Goblet cells are represented by larger light blue circles. Apoptotic cells are shown as small yellow circles. Necrotic cells are represented by outlined (in red for NGECs, blue for GCs) black circles. The amount of mucus is represented by green shading of the background: Lighter shades correspond to adequate amounts of mucus, whereas progressively darker areas reflect mucus depletion. (A) Viable goblet cells with an intact mucus layer under only mild to moderate stress. Bacteria are present but impeded from interacting with NGECs. (B) A more highly stressed system, with patchy areas of highly stressed cells with corresponding areas of mucus depletion (white outlined areas). Bacteria have not yet become adherent, and there are rare necrotic NGECs. (C) Progression to necrosis, with clusters of adherent bacteria and patches of apoptotic and necrotic cells. OS=oxidative stress.