Page 4 - Clinical Connections - Spring 2023

RVC RESEARCH STUDY VETERINARY SERVICES RVC.AC.UK
Equine
OSTEOARTHRITIS IN HORSES –
IS THERE A NEW OPTION?

Roger K.W. Smith, Professor of Equine Orthopaedics

he RVC Equine Referral Hospital However, the use of autologous stem cells was recorded for fourteen patients (eg
had a world-first 20 years ago, when carries limitations – they require obtaining figure 2) at pre-treatment and at six and
T it cultured mesenchymal stem cells the source material to culture the cells from, twelve weeks after treatment. Unfortunately,
from the bone marrow of a horse suffering technical expertise and an element of risk, two patients could not complete further
from an overstrain injury of its superficial particularly for aspiration of bone marrow assessment – one due to concurrent
digital flexor tendon. The cultured cells were from the sternum. Additionally, the second laminitis and one as it was euthanised due
implanted into the damaged tendon under stage in the process requires culture of the to the severity of their OA.
ultrasound guidance. cells in a VMD-licensed laboratory, which is
While we felt cell therapy might offer costly. These have limited the use of stem Figure 2: Scan
significant benefits for the treatment of cells. from a trial patient
tendon injuries, based on laboratory work, One way around these limitations is to
we did not realise how much we didn’t develop a stem cell product that is allogenic
know at the time. However, this spawned – i.e. cells derived from the same species
significant interest from around the world but a different individual. This means
and the use of autologous mesenchymal multiple doses can be prepared from the
stem cells became a commonly used same tissue of origin and supplied to the
treatment for both tendon and ligament veterinary surgeon ‘off the shelf’, making
injuries and osteoarthritis. their use much more convenient. However,
While the gradually accumulated clinical because the cells are derived from a different
outcome data from tendon injuries was individual, they can cause an allergic Over the twelve-week study, visual
generally positive, the evidence for the reaction when injected into the patient lameness significantly decreased by a mean
effectiveness in osteoarthritis was more unless they are carefully characterised to of 1.20 units (p=0.013). The evaluation of
variable. Nevertheless, the use of stem cells reduce the risk. the objective gait analysis also showed a
became keenly adopted as an option for In 2019, Boehringer Ingelheim obtained decrease in lameness, although this was
the treatment of inflammatory joint disease, a European-wide licence for an allogenic not statistically significant – most likely
especially in the USA. mesenchymal stem cell line, derived from because of the need to separate analysis
blood and developed by a company in into forelimb and hindlimb cases, which
Belgium. This cell product has also had the reduced the statistical power of the study.
cells ‘primed’ to make them more effective Interestingly, patients with a higher level
for the treatment of osteoarthritis (see of lameness on presentation responded
figure 1). to the treatment to a significantly greater
magnitude (p= 0.0156). It was also observed
RVC project that the decrease in lameness was greater at
After this product was launched, Boehringer twelve weeks than six (p=0.0368), showing
asked our Equine Referral Hospital to progressive improvement at a delay post-
undertake a simple case-based ‘trial’. This injection.
was structured to allow us to assess any These results support the concept that
change in lameness after treatment by re- stem cells can be beneficial for the treatment
examinations at six and twelve weeks after of one of the most common orthopaedic
treatment, using both the usual visual scoring problems in horses, although it also
and objective gait analysis, to minimise suggests that the treatment does not always
Figure 1: (A) Left (affected) and (B) the subjectivity assessment. This system result in complete soundness. This may not
unaffected hip joint from a 17-year-old of lameness assessment is becoming be surprising when the cases selected were
Warmblood gelding, which presented with a
marked left hindlimb lameness. mainstream in equine orthopaedics, and generally those more severely affected.
we have been using an in-house system, This simple clinical study also illustrates
(C) Right (affected) and (D) left (unaffected) developed by Dr Thilo Pfau of the Structure the opportunities afforded by a university
hip joints from a 60-year-old male (the
author!) taken on the same day. While hip and Motion Laboratory, for about ten years. equine hospital, which provides research
osteoarthritis is very common in humans, Recently, we concluded this trial and one opportunities to our talented veterinary
it is extremely rare in horses – and yet the of our students, Daniel Peterson, undertook students – fostering skills appropriate for
signs of joint collapse and new bone around
the joint are remarkably similar. The horse is assessment of the lameness data as part of continuing clinical research throughout their
considered an excellent large animal model a final year project, with interesting results. careers.
of many human musculoskeletal diseases. Visual and objective lameness assessment
For equine referrals, please call: 01707
666297
Email:
equinehospital@rvc.ac.uk

4 Spring 2023