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EQUINE MATTERS
The investigation and treatment of lameness
in horses is commonplace in equine veterinary
practice. Traditionally treatment of soft tissue
injuries and joint problems has focussed on
systemic non-steroidal anti-inflammatories such
as phenylbutazone (bute) which act largely
as painkillers, or a targeted approach with
steroids injected into a specific area such as
a joint. These treatments are effective at
alleviating pain and discomfort but do little
to stimulate repair of the structure involved.
There has been significant interest over the
last 20 years in regenerative medicine, with
its use becoming increasingly widespread
within equine practice. The most compelling
research has been in the area of stem cell
therapy.
Stem cells have the potential to differentiate
themselves to any cell type, including tendon
cells. Superficial digital flexor tendon injury
(Figure 1)
is a significant cause of lameness
within racing and eventing horses. Once
injured the tendon will heal, but loses its
natural elasticity which allows it to stretch
and recoil, instead becoming thick and
fibrous. Once a horse resumes work this
means the areas above and below the fibrous
area are at increased strain and more likely
to become re-injured. Stem cell therapy
involves collecting the horse’s own stem cells
from bone marrow in the sternum, these are
grown in lab conditions to multiply their
number and are re-injected into the injured
tendon. Within the tendon the stem cells
transform into more normal tendon tissue
during the healing process, rather than fibrous
tissue. Stem cell therapy will not speed up the
recovery, but it will mean that the tendon is
more mechanically normal and therefore the
horse is less likely to re-injure itself.
Platelets are small cell fragments, which
circulate in the blood; they stimulate clotting
and contain growth factors. Platelet Rich
Plasma (PRP) utilises these growth factors
because they stimulate formation of blood
vessels and connective tissue, which promote
healing. Currently PRP is used in the treatment
of tendon and ligament injuries. A blood
sample is collected from the horse and
filtered
(Figure 2)
to produce highly
concentrated plasma with large numbers
of platelets, that is then injected into the site
of injury.
Another technique increasingly used by
equine vets is called Autologous Conditioned
Serum (IRAP
®
); it is generally used in injuries
where inflammation is the source of pain.
Within an inflamed joint there are a number
of inflammatory proteins produced by the
horse, one of which is interleukin -1. A
sample of the horse’s own blood is taken
and incubated overnight with synthetic
beads coated in a substance to stimulate
the production of proteins which block
interleukin-1 and in doing so stop the
inflammation it induces. IRAP
®
is used in
treating arthritis, following arthroscopy
(keyhole surgery on joints) and in certain
ligament injuries.
The evidence base is strongest for stem cell
therapy, and further research into the field of
regenerative medicine is required to establish
the long-term effectiveness of these therapies,
but they do provide the prospect of better
long term recovery in musculoskeletal injuries.
REGENERATIVE MEDICINE
Veterinary surgeon
Tom Righton
XLEquine practice
Hook Norton
Veterinary Group
CASE REPORT...
Recent advances in the equine
industry:
regenerative medicine
Figure 1: Superficial digital flexor tendon
Figure 2: Filtering blood to produce
Platelet Rich Plasma
Tom Righton BVSc MRCVS,
Hook Norton Veterinary Group