Administration of extracellular vesicles derived from human amniotic fluid stem cells: a new treatment for necrotizing enterocolitis.

ABSTRACT

PURPOSE: Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease. Amniotic fluid stem cells (AFSC) improve NEC injury but human translation remains difficult. We aimed to evaluate the use of extracellular vesicles (EV) derived from human AFSC. METHODS: Human AFSC (hAFSC) were cultured according to the protocol (Celprogen Inc., California, U.S.A.). Conditioned medium was obtained, ultra-centrifuged, and EV were suspended in phosphate-buffered saline (PBS). C57BL/6 pups were grouped into (1) breast-fed (Control, n = 11); (2) NEC + placebo (NEC + PBS; n = 10); and (3) NEC + treatment (NEC + EV; n = 11). NEC was induced post-natal days P5-9 by (A) gavage feeding hyperosmolar formula; (B) hypoxia for 10 min; and (C) lipopolysaccharide. Intra-peritoneal injections of PBS or hAFSC-EV were given on P6-7. All animals were sacrificed on P9 and terminal ileum harvested. RESULTS: hAFSC-EV administration reduced intestinal injury (p = 0.0048), NEC incidence (score ≥ 2), and intestinal inflammation (IL-6 p < 0.0001; TNF-α p < 0.0001). Intestinal stem cell expression (Lgr5 +) and cellular proliferation (Ki67) were enhanced above control levels following hAFSC-EV administration (Lgr5 p = 0.0003; Ki67 p < 0.0001). CONCLUSION: hAFSC-EV administration reduced intestinal NEC injury and inflammation while increasing stem cell expression and cellular proliferation. hAFSC-EV administration may induce similar beneficial effects to exogenous stem cells.