To validate the induction of proinflammatory endothelial cells in NEC, we performed single-molecule fluorescence in situ hybridization (smFISH) for the endothelial/lymphatic-specific marker CLDN5 along with SELE as a specific marker of endothelial activation, and identified elevation in SELE+ endothelial cells in NEC (Fig 4J and 4K). Here, CLDN5 is linked to necrotizing enterocolitis.