Equine mesenchymal stem cells derived from endometrial or adipose tissue share significant biological properties, but have distinctive pattern of surface markers and migration.

Adult stromal mesenchymal stem cells (MSCs) have been postulated as responsible for cell renewal in highly and continuously regenerative tissues such as the endometrium. MSCs have been identified in the endometrium of many species including humans, rodents, pets and some farm animals, but not in horses. The objective of this work was to isolate such cells from the endometrium of mares and to compare their main biological attributes with horse adipose-derived MSCs. Here we successfully isolated and characterized endometrial MSCs (eMSCs) from mares. Said cells showed fibroblast-like morphology, grew on plastic, had doubling population times of 46.4 ± 3.38 h, underwent tri-lineage (osteo, chondro and adipogenic) differentiation after appropriate inductions, migrated toward the attraction of fetal calf serum and displayed a pattern of surface markers commonly accepted for horse MSCs. All these are properties of MSCs. Some of these attributes were shared with equine adipose-derived MSCs, but the migration pattern of eMSC at 12 and 24 h after stimulation was reduced in comparison with adipose MSCs. Also, expression of CD44, CD90 and MHCI surface markers were dramatically down-regulated in eMSCs. In conclusion, equine-derived endometrial MSC share biological attributes with adipose MSC of this species, but displayed a different surface marker phenotype and an impaired migration ability. Conceivably, this phenotype is distinctive for MSC of this origin.