Mesenchymal stem cells are multipotent cells found in a number of tissues that can differentiate into various cell types. As such, they provide an enormous potential for regenerative medicine. Such progenitor cells have been used clinically for about 15 years to treat several tendon and joint conditions in horses.

Until now, the stem cells, however, needed for therapeutic purposes have usually been harvested surgically from the animals’ bone marrow or fat tissue. Researchers from the Vetmeduni Vienna Centre for Artificial Insemination and Embryo Transfer, in Austria, have, for the first time, successfully harvested stem cells from a horse’s horses. The procedure requires no surgical intervention and the laboratory results show that the cells differentiate into cartilage and other tissues.

Unlike bone marrow or fat tissue, the uterus can be accessed nonsurgically using small instruments inserted via the cervix.

“While the human endometrium is known to harbour stem cells, these had previously not been identified in equine endometrium,” say Elisabeth Rink, MagMedVet. and Christine Aurich, DVM, PhD, from the Vetmeduni Vienna Centre for Artificial Insemination and Embryo Transfer.

The pair worked with an international team with Xavier Donadeu, DVM, MS, PhD, from the University of Edinburgh’s Roslin Institute, in Scotland, and Hilari French, DVM, PhD, from Ross University School of Veterinary Medicine, in Saint Kitts and Nevis, to confirm the presence of stem cells in the endometrial tissue of horses. The data on the isolation, culture and characterization of mesenchymal stem cells from the equine endometrium was published in the journal Stem Cell Research and Therapy.

For the study, the researcher collected uterine tissue samples from six mares. The team then separated suspected stem cells from endometrial epithelial cells and expanded these in culture. Then, they identified the isolated cells as potential stem cells using various molecular biology techniques.

“The laboratory analyses, such as immunohistochemistry, genetic analysis and flow cytometry, aimed to identify the stem cells through specific cell markers (i.e., the expression of genes and the presence of certain surface proteins),” explains Rink. For comparison with the endometrial cells, stem cells obtained from the bone marrow by traditional surgical techniques were analysed in the same way.

Cells obtained from the uterus expressed the same markers as bone marrow stem cells. Furthermore, the scientists were able to show in cell culture conditions that the endometrial stem cells differentiated into fat, bone, cartilage, and muscle cell lines.

“The endometrium provides a source of mesenchymal stem cells that can be easily accessed with little stress to the animals,” says Aurich. “The cell culture results show that these cells can be of benefit not only in the treatment of uterine conditions, but that they can also replace the need for surgically obtained stem cells for therapeutic purposes in other tissue types.”

The study, “Isolation and characterization of equine endometrial mesenchymal stromal cells,” was published in Stem Cell Research and Therapy.