(E58) Placental-derived Extracellular Vesicles Enhance in vitro Equine Intestinal Epithelial Repair

Abstract:

Background:
Colic is the most common equine killer beyond old age. Severe colic results in intestinal epithelial barrier breakdown and no existent therapies directly enhance epithelial recovery. Equine placental extract (ePE) accelerates restitution and tight junction recovery (pending publication). Primed placental derived stem cells produce extracellular vesicles (EVs) that enhance epithelial healing in other species.

Hypothesis:
Naïve, hypoxia-primed, and LPS-primed EVs will increase in vitro equine intestinal epithelial repair.

Animals:
Jejunal enteroids were isolated from four hospitalized horses euthanized for non-gastrointestinal causes. Healthy placental membranes from three university-owned mares were processed for ePE and EV isolation.

Methods:
Human placental stem cells (hPSC) were exposed to LPS, hypoxia (5% oxygen) or nothing (naïve) for 48 hours (H). Media was ultra-filtered and chromatographically fractionated to recover hEVs (35-350nm).
Equine jejunal monolayers were injured with 4H hypoxia and scratch wounding, and then apically treated with hEVs or PBS. Scratch margins were measured every 6H until closure. Scratch closure was analyzed using two-way ANOVA and Tukey multiple comparison.
Equine chorioallantois was chemically digested to create ePE, and then ultracentrifuged to collect EVs, as confirmed by transmission electron microscopy.

Results:
LPS-primed hEVs accelerate wound closure at 6H (control: 61.2%, LPS-EV: 66.9%, p= 0.002). At 12H, LPS and hypoxia-primed hEVs hasten wound closure (control: 82.5%, LPS-EV: 92.2%, p= 0.003; hypoxia-EV: 90.8%, p= 0.0011). EVs were successfully isolated from ePE.

Conclusions and Clinical Importance:
Primed placental hEVs increase early epithelial restitution. ePE containing EVs may provide a targeted therapeutic to accelerate epithelial repair in equine colic patients.