Hexapeptides from human milk prevent the induction of oxidative stress from parenteral nutrition in the newborn guinea pig.

Introduction: In preterm neonates, peroxides contaminating total parenteral nutrition (TPN) contribute to oxidative stress, which is suspected to be a strong inducer of hepatic complications related to prematurity. Recently, others reported that hexapeptides derived from human milk (HM) exerted free radical-scavenging activities in vitro. Therefore, the aim of this study was to assess the capacity of these hexapeptides to limit the generation of peroxides in TPN and to prevent TPN-induced hepatic oxidative stress.
Methods: At 3 d of life, guinea pigs were infused, through a catheter in jugular vein, with TPN containing or not peptide-A (YGYTGA) or peptide-B (ISELGW). Peroxide concentrations were measured in TPN solutions, whereas glutathione, glutathionyl-1,4-dihydroxynonenal (GS-HNE) and mRNA levels of interleukin-1 (IL-1) and tumor necrosis factor-α (TNFα) were determined in liver after 4 d of infusion.
Results: The addition of peptide-A to TPN allowed a reduction in peroxide contamination by half. In vivo, peptide-A or peptide-B corrected the hepatic oxidative status induced by TPN. Indeed, both peptides lowered the hepatic redox potential of glutathione and the level of GS-HNE, a marker of lipid peroxidation. As compared with animals infused with TPN without peptide, the hepatic mRNA levels of IL-1 and TNFα were lower in animals infused with TPN containing peptide-A or peptide-B.
Discussion: These results suggest that the addition of YGYTGA or ISELGW to TPN will reduce oxidative stress in newborns. The reduction in mRNA of two proinflammatory cytokines could be important for the incidence of hepatic complications related to TPN.