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June 2017 THE HORSE TheHorse.com
different role entirely.
"Stem cells never perform as well as
differentiated cells in synthesizing new
tissue," says Smith. "Current theories
with more evidence are that these cells
are not regenerative—instead they
modulate (reduce) inflammation, and
this appears to be their main mechanism
of action."
In other words, researchers originally
hoped that stem cells would simply re-
place the cells in the target tissue (which
can be done reliably in the laboratory
but not the live horse). But, instead, it
appears stem cells have a different role,
helping direct the healing process of in-
jured and damaged tissues, with the end
product more like native tissue.
A New Generation of
Regenerative Medicine
Many researchers, mainly in the United
States and Europe, have been looking to
produce a new generation of stem cell
therapy. Spaas says his group has found
it's possible to use healthy donor cells,
divided into large batches for reduced
costs, and "predifferentiate" them in the
laboratory—to "tell" them to become
the right cells, prior to injection. He and
colleagues have been researching this yet-
unreleased off-the-shelf therapy, with en-
couraging results, and are awaiting their
work's publication in a peer-reviewed
journal.
The next steps for stem cell research, in
general, says Smith, involve:
■ Better retention of stem cells in the
horse's body;
■ Understanding of the effects of multiple
dosing;
■ Validating the effects of allogenic (com-
ing from another horse, as in Spaas'
work) stem cell therapy; and
■ Better understanding of inflammation's
role in tendon and ligament healing
process, and how mesenchymal stem
cells influence it.
Take-Home Message
Tendon and ligament injuries do heal
on their own, and rest remains the best
home treatment. Left-to-heal structures,
however, are more prone to re-injury and
likely to get re-injured. To preserve your
horse's performance future, you can turn
toward treatments aimed at improving the
healing process. And as researchers keep
investigating ways to heal injured tendons
and ligaments, we can remain optimistic
that these cases will no longer be career-
ending—only career- postponing.
h
A veterinarian injects stem cells into an injured
tendon.
DUSTY
PERIN