Stem cells have been used therapeutically in horses for many years as a treatment option for tendon and joint injuries, but these cells are commonly obtained surgically from bone marrow or fat tissue.

Researchers from Veterinarmedizinische Universitat Wein (Vetmeduni Vienna) in Austria have, for the first time, managed to harvest stem cells from the mucous membrane of the equine uterus. By taking stem cells from the uterus without the need for surgical intervention, the procedure provides an alternative with reduced pain and stress for the animals, the announcement said.

Mesenchymal stem cells are multipotent cells found in a number of tissues that can differentiate into various cell types. Thus, stem cells 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.

Researchers from the Centre for Artificial Insemination & Embryo Transfer at Vetmeduni Vienna developed the procedure, and laboratory results showed that the cells differentiate into cartilage and other tissues.

Unlike bone marrow or fat tissue, the uterus can be accessed non-surgically using small instruments inserted via the cervix. The harvest of mesenchymal stem cells from the endometrium -- the mucous membrane of the uterus -- could, therefore, contribute to a reduction of surgical and invasive experiments in animals, Vetmeduni Vienna said.

“While the human endometrium is known to harbor stem cells, these had previously not been identified in equine endometrium,” said Elisabeth Rink and Christine Aurich from the Centre for Artificial Insemination & Embryo Transfer.

The two researchers, in an international team with Xavier Donadeu from the Roslin Institute at the University of Edinburgh in Scotland and Hilari French from the Ross University School of Veterinary Medicine in Saint Kitts & Nevis, have now managed 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 were published in the journal Stem Cell Research & Therapy.

Extended options

For the study, uterine tissue samples were collected from six mares. The team separated suspected stem cells from endometrial epithelial cells and expanded these in cell culture. The isolated cells then were identified 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,” first author Rink explained. For comparison with the endometrial cells, stem cells obtained from the bone marrow by traditional surgical techniques were analyzed in the same way.

Cells obtained from the uterus clearly expressed the same markers as bone marrow stem cells, according to the researchers. 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. 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,” Aurich concluded.