Exploring Stem Cells for Wounds in Horses: Promoting Healing, Preventing Infection

Although a pilot study did not identify any benefits of using a “stem cell secretome” on horses for promoting tissue regeneration or fighting infection, veterinary scientists are still pursuing this avenue of research.^* According to the researchers, this pilot study lays the foundation for future work that will more fully explore the role of the equine stem cell secretome in wound management.

In the pilot study, two horses were used, and six surgical wounds were made on each side of their bodies. Wounds on the left side of each horse were inoculated with methicillin-resistant Staphylococcus aureus (MRSA). For three days following surgery and inoculation, two wounds on each side of the thorax were treated with either (1) an antibiotic ointment (mupirocin) to serve as a positive control, (2) stem cell secretome, or (3) a negative control (culture medium). All wounds were evaluated until 28 days after surgery to assess bacterial colonization and wound closure.

The stem cells were obtained from blood cells (peripheral blood monocytes) collected from a single horse that was not one of the horses used in this study. Those stem cells, also called mesenchymal stromal/stem cells, were cultured in the laboratory and the culture medium used to provide nutrients for the cells was collected. This culture medium contains bioactive factors such as growth factors and antimicrobial products produced by the stem cells.

“MRSA was selected to inoculate surgical wounds as this bacterium is a concern in the equine community, often found in cutaneous wounds, and has the potential to infect humans. Thus, having a simple treatment option for promoting wound healing and preventing infection from pathogens such as MRSA would be invaluable,” explained Ashley Fowler, Ph.D., a Kentucky Equine Research nutritionist.

Unfortunately, this pilot study, which is the first study to assess stem cell secretome in wound healing in live horses, did not identify any positive effects compared to the controls. Specifically, the secretome did not decrease bacterial numbers in any of the wounds. In the same vein, the secretome did not have any beneficial effects on wound size or healing.

“The scientists did report, however, that laboratory studies and studies conducted in other species demonstrate that using stem cell secretome is a promising treatment option for wound healing. They recommended additional studies with a larger sample size and made specific recommendations for improving the study design,” Fowler said.

Horses are prone to injuries with traumatic wounds being the second most common emergency treated by veterinarians. Wound healing can be complex, particularly for those occurring on the lower limbs where limited skin and blood supply can result in prolonged healing or proud flesh.

“Supplying the body with the building blocks for healthy skin may support wound recovery. Bio-Bloom-PS is a coat and hoof supplement that contains biotin, iodine, bioavailable zinc, and essential amino acids and fatty acids that all work together to promote healthy skin and coat,” Fowler said.

 ^*Fahey, M.J., R.M. Harman, M.A. Thomas, B.R. Pugliese, J. Peters-Kennedy, M.L. Delco, and G.R. Van de Walle. 2024. Preliminary in vivo investigation of the mesenchymal stromal cell secretome as a novel treatment for methicillin-resistant Staphylococcus aureus in equine skin wounds. Veterinary Surgery 53(8):1377-1389.