L-arginine can be converted to endogenous nitric oxide (NO) by endothelial nitric oxide synthase (eNOS), thereby enhancing intestinal perfusion, reducing the detrimental effect of endothelial receptor toll-like receptor 4 (TLR4) activation and mitigating NEC intestinal damage (Yazji et al., 2013). The gene discussed is TLR4; the disease is necrotizing enterocolitis.