TLR4 and necrotizing enterocolitis: However, studies that mechanistically link Paneth cells and TLR4 have not been previously performed in regard to NEC because the majority of animal models of NEC either do not contain Paneth cell lineages (piglet) or are performed in animals prior to normal ontological development of Paneth cells (hypoxia/formula rodent models) (Bry et al., 1994).