Hepatocyte growth factor in human breast milk acts as a trophic factor

To evaluate the significance of hepatocyte growth factor (HGF) in milk in the perinatal period, we examined immunoreactive HGF levels and bioactivity in human milk. Human milk samples were obtained from women at various postpartum ages, and the levels of HGF were measured by ELISA. In the cross sectional study, the concentration of milk HGF from term deliveries showed a significant inverse correlation with progress of lactation, whereas in cases of preterm delivery concentrations, levels remained high after a long period of lactation. In the longitudinal analysis, the contents of HGF in colostrum, transitional, and mature milk from preterm deliveries were significantly be higher than those from term deliveries. Although mature milk from term and preterm deliveries contained significantly lower levels of HGF than colostrum, high levels of HGF persisted in mature milk from preterm deliveries. After partial purification, immunoblotting analysis showed the presence of both alpha- and beta-chains of HGF. HGF in milk stimulated proliferation of rat hepatocytes in primary culture, which was inhibited by supplementation with anti-HGF antibody. Thus, a high concentration of bioactive HGF is present in human milk in the postpartum period. Our results suggest that HGF in milk acts as a trophic factor for the gastrointestinal tract in neonates.