1Ra). Research has also been aimed at bone marrow-derived mesenchymal
stem cells, adipose-derived stromal vascular fraction and platelet-rich plasma
(PRP).
PRP is an autologous therapy increasing in human and veterinary medicine.
Numerous studies have examined the effects of PRP in vitro and in vivo and
have demonstrated beneficial effects which includes improved cellular
remodeling and decreased time to healing.
PRP has been classically described as “a volume of plasma that has a
platelet count above baseline” [4]. It can also be defined as an autologous
biological product produced from whole blood, that has a high platelet
concentration [6]. These definitions would suggest a pure mixture of plasma
(the acellular, liquid portion of blood that contains proteins for clotting and
other bioactive molecules) and platelets (and their associated growth factors
(GFs) and cytokines). The generic term “PRP” has recently expanded to
include a variety of final products. To more precisely delineate these products
based on their leukocyte and fibrin content, they have been called pure PRP,
leukocyte-rich PRP, pure platelet-rich fibrin and leukocyte- and platelet-rich
fibrin. The terms “platelet-rich concentrate” and “platelet concentrate” are also
used for PRP [4].
Numerous studies have quantified differences in the cellular and biochemical
profiles of various human autologous platelet concentrates (APC) products. A
target platelet concentration of 109/ml in APCs (three to four times the
concentration of platelets in comparison to that of whole blood in humans) has
been suggested to produce the best clinical results for bone regeneration, but
there is a lack of evidence for other indications [7,8]. In horses the optimal
concentrations for clinical use have not yet been defined.
The therapeutic bases of platelet-derived products are derived from the
platelet growth factor content and the absolute number of the platelets
themselves. Platelet concentration is positively correlated to growth factor
concentration, although there are individual variation in the concentration of
GFs released from granules [10]. GF concentration typically contain a 3- to 5fold increase in platelet concentrate compared to baseline values [10].
In horses, PRP is most often used as a percutaneous, ultrasound-guided,
intra-lesional treatment for tendon and ligame nt injuries. It is most often
applied as a single injection, but is administered repeatedly per lesion by
some clinicians; optimal administration protocols have not been determined.
PRP is generally administered as a single agent but alternatively can be
applied in combination with stem cells. PRP use for treatment of equine joints
has been anecdotally reported, although there is currently much less scientific
support for treatment of arthropathies than for tendon injuries [9].
The current study performed investigated the clinical signs, synovial fluid
cytology and growth factor concentrations after intra-articular PRP in horses
with osteoarthritis.
The objectives were to (1) report the differences in clinical signs and synovial
cytology after intra-articular injection of PRP into osteoarthritic joints and
normal equine joints, (2) to determine and compare growth factor
concentrations in the synovial fluid of normal equine joints and osteoarthritic
15-‐18
February
2016
East
London
Convention
Centre,
East
London,
South
Africa
126