HBB and necrotizing enterocolitis: The Si-NEC DEGs were highly enriched with upregulated genes related to hypoxia (see the “Results” section) and downregulated transcripts encoding HBB and its synthetase ALAS2. Hemoglobin beta (HBB) is known to be expressed in neurons [72], hippocampal astrocytes, and mature oligodendrocytes [73] and is neuroprotective against oxidative and nitrosative stresses [74].