Use of equine embryo -derived mesenchymal stromal cells and their extracellular vesicles as a treatment for persistent breeding-induced endometritis in susceptible mares.
Authors: Hollinshead F K, Hanlon D W, Hou W, Tasma Z, Damani T, Bouma G J, Murtazina D A, Chamley L
Journal: Journal of equine veterinary science
Summary
Persistent breeding-induced endometritis (PBIE) undermines fertility in susceptible mares by triggering excessive uterine inflammation and fluid accumulation after mating; whilst antimicrobial protocols exist, they don't consistently resolve the underlying inflammatory pathology or restore optimal endometrial receptivity. Hollinshead and colleagues trialled embryo-derived mesenchymal stromal cells (EDMSCs) and their extracellular vesicles (EVs)—bioactive membrane-bound particles that mediate intercellular communication—as intrauterine pre-breeding therapies, using both a controlled experimental model (five PBIE-susceptible mares challenged with dead sperm) and a clinical cohort (37 client-owned mares across 40 cycles). Both cell and EV treatments significantly reduced post-breeding fluid accumulation; pregnancy rates per first cycle were 47% and 65% respectively (versus historically poor outcomes in PBIE-susceptible animals), rising to 67% and 79% by season's end. These findings represent preliminary but promising evidence that EDMSCs or their EVs could offer practitioners a targeted immunomodulatory alternative for managing PBIE, though larger, controlled breeding trials are needed before adoption into routine practice. The accessibility of embryonic tissue as a cell source and the potential advantages of acellular EV therapy warrant further investigation, particularly given the substantial economic and welfare implications of subfertility in breeding mares.
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Practical Takeaways
- •EDMSCs and their extracellular vesicles offer a novel, non-antimicrobial therapeutic option for managing infertility in mares with persistent breeding-induced endometritis
- •Intrauterine treatment with these cell products significantly improves pregnancy rates in susceptible mares, with EV-treated mares showing higher conception rates (79% by season-end) than EDMSC-treated mares
- •This therapy addresses a significant breeding management challenge by creating an optimal uterine environment without relying on traditional antibiotic or anti-inflammatory protocols
Key Findings
- •Embryo-derived mesenchymal stromal cells (EDMSCs) and their extracellular vesicles significantly reduced intrauterine fluid accumulation post-breeding in PBIE-susceptible mares
- •First-cycle pregnancy rate was 47% with EDMSC treatment and 65% with EDMSC-derived EV treatment
- •End-of-season pregnancy rates reached 67% with EDMSC treatment and 79% with EV treatment in susceptible mares
- •This is the first clinical report of EDMSCs or their EVs as intrauterine therapy for managing PBIE in mares