Getting a subfertile mare in foal usually often necessitates repeated veterinary examinations and treatments, such as medications and uterine flushes. Still, success is not always guaranteed. Researchers recently revealed that stem cells and other biologic therapies might also be useful in the quest to promote “sub” mares to fully fertile.
Ryan Ferris, DVM, MS, Dipl. ACT, of Colorado State University’s Equine Reproduction Laboratory, described how these biologic therapies—generally used for a variety of musculoskeletal injuries or soft tissue injuries–could have reproductive applications, at the 2012 American Association of Equine Practitioners’ (AAEP) Convention, held Dec. 1-5 in Anaheim, Calif.
“All mares have a transient inflammatory response in the uterus to spermatozoa following mating or insemination,” explained Ferris. “This results in white blood cells and fluid accumulating in the uterine lumen. Uterine contractions result in this fluid being cleared from the uterus within 24 hours post-breeding, but approximately 20% of mares of mares are unable to clear this inflammatory response to spermatozoa by 24-48 hours post-mating.”
Traditional treatments for post-mating inflammation include systemic glucocorticoid steroids, which can in some cases cause laminitis, prevent ovulation, and suppress the immune system.
“Additional treatments such as uterine lavage or (systemic) ecbolics (agents that increase uterine contractions) are typically only used after the inflammatory response has occurred,” said Ferris.
Alternate therapies that are relatively noninvasive and do not cause side effects would, therefore, be advantageous.
Together with David Frisbie, DVM, PhD, Dipl. ACVS, ACVSMR (sports medicine), who is renowned in the equine industry for his work with IRAP (a type of biologic therapy used extensively for joint disease), Ferris evaluated how well stem cells (MSCs) and autologous conditioned serum (ACS) controlled uterine inflammation. To do this, they used 800 million dead spermatozoa to induce an inflammatory response in six mares. The team monitored the resulting inflammation using a variety of clinical and biochemical endpoints.
Their key findings were:
- Both ACS and MSCs decreased evidence of inflammation by a reducing the number of neutrophils (a class of white blood cells) as compared to a placebo treatment; and
- Increased concentrations of the anti-inflammatory mediator interleukin-1Ra wereidentified after MSC treatment, but no difference in interleukin-1Ra was noted after ACS treatment.
“These preliminary results suggest that biologic therapies can alter the immune response in mares following mating,” summarized Ferris. “Because a variety of bioactive substances could be involved in this response, more research is needed.”
In other words, researchers aren’t certain what exactly aspects of MSC and ACS treatment could be modifying these mares’ uterine environments, but the exciting preliminary results support future work in this field. They also need to more closely examine the impact of ACS and MSCs on pregnancy rates in subfertile mares to prove its benefits.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.