Exosomes derived from colostrum and mature human breast milk protect against experimental necrotizing enterocolitis

Human milk-derived exosomes can protect intestinal organoids from lipopolysaccharide induced injury. The aim of this study is to investigate effects of exosomes derived from different periods of lactation on intestinal injury caused by experimental necrotizing enterocolitis (NEC).

Colostrum and mature milk from healthy lactating human mothers were collected and isolated exosomes using serial ultracentrifugation and filtration. NEC was induced in mice pups by hypoxia, gavage of feeding of formula, and lipopolysaccharide (LPS) administration between postnatal days 5 and 9. Breast-fed pups were used as controls. NEC groups received daily gavage feeding of formula with added phosphate-buffered saline (PBS), colostrum exosomes or mature breast milk exosomes. The distal ileum was examined for NEC histology, inflammatory cytokines, and intestinal regeneration abilities.

Compared to NEC group, administration of colostrum and mature milk exosomes in NEC mice resulted in a significant reduction in histological scores of intestinal tissues and decreased expression of inflammatory genes IL-6 and TNF-α. Furthermore, the expression of PCNA, as well as stem cell markers (Lgr5 and Olfm4), increased following exosome treatment, with a corresponding rise in the immunofluorescence staining of Ki67. Compared to mature breast milk exosomes, colostrum exosomes were more effective at enhancing enterocyte proliferation and intestinal regeneration.

Human milk-derived exosome treatment decreases the severity of experimental NEC. Colostrum exosomes induce greater intestinal regeneration compared to mature breast milk exosomes.