title: Breast milk-derived exosomes promote intestinal epithelial cell growth.
abstract: BACKGROUND
  Breast milk administration prevents necrotizing enterocolitis (NEC). However, the mechanism remains unclear. Exosomes are cell-derived vesicles highly present in human milk and regulate intercellular signaling, inflammation, and immune response. We hypothesized that milk-derived exosomes beneficially affect intestinal epithelial cells.
  
  
  METHODS
  Rat milk was collected, and exosomes were isolated using ExoQuick reagent and visualized by Nanoparticle Tracking Analysis. Protein was extracted from encapsulating exosomes, and concentration was measured. 2×104intestinal epithelial cells (IEC-18) were treated for five hours with 0.5-μg/μl exosomes, an equal volume of exosome-free milk, or control solution (PBS). IEC-18 viability was measured using a colorimetric assay (MTT), and gene expression was analyzed by qRT-PCR. Data were compared using one-way ANOVA with Bonferroni post-test.
  
  
  RESULTS
  Rat milk was collected, and exosome isolation was confirmed. Compared to control, treatment with exosomes significantly increased IEC viability, proliferation, and stem cell activity (all p<0.05). However, administration of exosome-free milk had less significant effects.
  
  
  CONCLUSIONS
  Rat milk-derived exosomes promote IEC viability, enhance proliferation, and stimulate intestinal stem cell activity. These findings provide insight into the mechanism of action of breast milk in the intestines. Exosome administration is a promising prevention method for infants at risk of developing NEC when breastfeeding is not tolerated.
authors.affiliation: Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Alison
authors.initials: A
authors.lastname: Hock
authors.affiliation: Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Hiromu
authors.initials: H
authors.lastname: Miyake
authors.affiliation: Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Carol
authors.initials: C
authors.lastname: Lee
authors.affiliation: Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Ermini
authors.affiliation: Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Yuhki
authors.initials: Y
authors.lastname: Koike
authors.affiliation: Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Pekka
authors.initials: P
authors.lastname: Määttänen
authors.affiliation: Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Augusto
authors.initials: A
authors.lastname: Zani
authors.affiliation: Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada. Electronic address: agostino.pierro@sickkids.ca.
authors.forename: Agostino
authors.initials: A
authors.lastname: Pierro
mesh_terms: D000818:Animals; D001942:Breast Feeding; D049109:Cell Proliferation; D002470:Cell Survival; D020345:Enterocolitis, Necrotizing / Q000517:prevention & control; D004847:Epithelial Cells / Q000502:physiology*; D055354:Exosomes / Q000502:physiology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007413:Intestinal Mucosa / Q000502:physiology*; D008892:Milk / Q000166:cytology* / Q000502:physiology; D051381:Rats
keywords: Breast milk; Cell viability; Exosome; Necrotizing enterocolitis (NEC); Proliferation