The Fate of Autologous Endometrial Mesenchymal Stromal Cells After Application in the Healthy Equine Uterus

Abstract

Because of their distinct differentiation, immunomodulatory, and migratory capacities, endometrial mesenchymal stromal cells (MSCs) may provide an optimum source of therapeutic cells not only in relation to the uterus but also for regeneration of other tissues. This study reports the fate of endometrial MSCs following intrauterine application in mares. Stromal cell fractions were isolated from endometrial biopsies taken from seven reproductively healthy mares, expanded, and fluorescence labeled in culture. Phosphate-buffered saline (PBS) or MSCs (15 × 106) were autologously infused into each uterine horn during early diestrus and subsequently tracked by fluorescence microscopy and flow cytometry of endometrial biopsies and blood samples taken periodically after infusion. The inflammatory response to cell infusion was monitored in endometrial cytology samples. MSCs were detected in endometrial sections at 6, 12, and 24 h, but not later (7 or 14 days), after cell infusion. Cells were in all cases located in the uterine lumen, never within the endometrial tissue. No fluorescence signal was detected in blood samples at any time point after infusion. Cytology analyses showed an increase in % of polymorphonuclear neutrophils between 1 and 3 h after uterine infusion with either MSCs or PBS and a further increase by 6 h only in mares infused with PBS. In summary, endometrial MSCs were detected in the uterine lumen for up to 24 h after infusion, but did not migrate into the healthy endometrium. Moreover, MSCs effectively attenuated the inflammatory response to uterine infusion. We conclude that endometrial MSCs obtained from routine uterine biopsies could provide a safe and effective cell source for treatment of inflammatory conditions of the uterus and potentially other tissues.

Comparison of Antibacterial and Immunological Properties of Mesenchymal Stem/Stromal Cells from Equine Bone Marrow, Endometrium, and Adipose Tissue

“…The identification of novel MSC sources has also represented a step forward in that regard. For example, although BM and AT are well-established sources of clinical MSCs in both humans and animals, EM is now emerging as a promising alternative source with defined cell differentiation and immunomodulatory properties [ 23 , 24 , 30 , 33 ]. It is thus critical to compare the immunomodulatory properties of MSCs across different tissues to identify the most optimal source(s) for particular clinical application.…”

Persistent Breeding-Induced Endometritis in Mares—A Multifaceted Challenge: From Clinical Aspects to Immunopathogenesis and Pathobiology

“…A report found that MSC administration decreases neutrophil numbers and increases anti-inflammatory ILRN expression in the endometrium of the normal mare [342]. Interestingly, while one study found that MSCs also attenuate markers of uterine inflammation following treatment, cells were unable to penetrate the endometrium and remained within the uterine lumen [343]. However, another study reported that intrauterine infusion of MSCs effectively engrafted MSCs in periglandular spaces [344].…”

Edition of Prostaglandin E2 Receptors EP2 and EP4 by CRISPR/Cas9 Technology in Equine Adipose Mesenchymal Stem Cells

“…In horses, the vast majority of reports on the medical use of MSCs are for the treatment of injuries of skeletal muscle, cartilages, and ligaments, which are the main causes of reduced performance in equine athletes, leading to important health and economic issues [ 36 ]. MSCs have also been used in mares with endometrial diseases [ 37 , 38 ]. The underlying cause of all these pathologies is inflammation, of which PGE2 is a key mediator.…”

“…The herein reported transduction efficiency and cell recovery did not greatly differ from other MSC reports. Nevertheless, using FACS separation yields a comparative benefit for selection compared to other methods, such as limiting dilution, which is time consuming, of low throughput, and does not necessarily guarantee clonality [ 37 ], nor antibiotic selection [ 38 ], which could impair cell growth after editing.…”