The art (and existing science) of regenerative medicine in equine practice, and whats to come
Regenerative therapy is an umbrellaterm encompassing any method that encourages the body to self- heal. Because it is drawing onits own properties, healing tissue more closely resembles native tissue than weak, disorganized scar tissue typically seen post-injury.
The goal is to allow restoration of normal function and structure of the injured tissue to allow horses to perform at their previous level, whatever that might be, with a reduced risk of reinjury, says Kyla Ortved, DVM, PhD, Dipl. ACVS, ACVSMR, assistant professor of large animal surgery at the University of Pennsylvanias New Bolton Center, in Kennett Square.
She says the three main components of regenerative medicine that help tissues self-heal include:
A specific therapy may incorporate some or all three of these components, says Ortved.
Due to the regenerative therapy industrys popularity and continued growth, many articles weve published review recent laboratory studies about stem cell production and data on efficacy andsafety (you can find them at TheHorse.com/topics/regenerative-medicine). Here, well review the basics of three regenerative modalities commonly used in equine medicine and when veterinarians and horse owners might consider each.
With this approach the practitioner collects blood from a horse and processes it using a commercial system that concentrates the platelets. When he or she injects that concentrated platelet product back into the horse, granules within the platelets release an array of growth factors that aim to facilitate and modulate the healing process. Specifically, granule-derived growth factors encourage target tissue cells at the injury site to migrate and proliferate, improve extracellular matrix synthesis, and stimulate blood vessel development.
Recently, leukocyte-reduced PRP hasbecome many equine veterinarians PRP product of choice. These preparations contain fewer white blood cells (leukocytes) and, reportedly, inflammatory mediators than normal PRP products do. These mediators break tissues down, effectively counteracting the anabolic (tissue-building) effects of the platelets and their granules.
Veterinarians can easily prepare ACS by collecting a blood sample from the patient, then incubating it with special commercially available glass beads to stimulate interleukin-1 receptor antago- nist protein (IRAP) production. Theythen inject the resultant IRAP-rich serumsample back into the patient at the target location or injury site. This protein blocks the action of interleukin-1, a powerful and damaging pro-inflammatory mediator. Additionally, glass bead incubation stimulates the production of anti-inflammatory mediators and growth factors similar to those found in PRP.
Ortved says its important to remember that all biologics, including PRP and IRAP, contain various concentrations of growth factors and bioactive protein.
Remember, they are made from your horses blood and, therefore, containall of the components in blood, just in varying concentrations, she says.
Regenerative therapies that contain highconcentrations of IRAP include IRAP II, autologous protein solution (APS), and bone marrow aspirate concentrate (BMAC).
In certain tissues, such as adipose (fat) and bone marrow, we can find specific cells that have the ability to self-renew and grow more than 200 types of body cells. Veterinarians can isolate these cells, called stem cells or progenitor cells, and either:
Perhaps more important than theirability to differentiate into other celltypes, stem cells have powerful anti-inflammatoryproperties and play acentral role in coordinating healing in alltypes of tissues through cell-to-cell signaling,Ortved says.
Which of these three modality typeswill provide the most benefit to yourhorse depends on a variety of factors thatyou and your veterinarian will consider.