Induction of NEC in Caco-2 cells led to substantially enhanced expression of both PARP1 and PAR compared to the control Caco-2 cells (Fig. 6A–C), together with significantly increased cell death in Caco-2 cells characterized by double-positive staining for 7-ADD and Annexin V as revealed by FACScan analysis (Fig. 6D, E). Here, PARP1 is linked to necrotizing enterocolitis.