November Newsletter
This past weekend I had the privilege of attending and
speaking at the 5TH International Conference on Laminitis and
Diseases of the Foot. This meeting takes place right here in our back yard
every other year and serves as a forum for the brightest minds from all over
the world who are collectively trying to unravel the mystery of laminitis.
Hopefully one day soon we will discover the key which would unlock a cure for
this debilitating disease. Not only does this meeting concentrate the
researchers, but also brings veterinary practitioners, farriers, and concerned
horse owners together under the same roof for a few days.
Unfortunately for me, as a speaker and meeting
moderator, I was unable to hear all the presentations that were of interest to
me. There were so many great topics and speakers and thank goodness their
presentations are all summarized in the proceedings. So, as I was reading
through the proceedings I thought that a summary of some of the more practical
and useful ones would be a great thing to pass on to all of you.
One of the most interesting findings is the discovery
of inflammatory enzymes found in high concentrations in the laminae of horses
suffering from laminitis caused by carbohydrate overload and black walnut toxicosis.
Known as MMP-2, MMP-9, and ADAMTS-4, these metalloproteinases break down
proteins and proteoglycans, and are found in the laminae early in the disease
and may directly cause damage to the tissue, the constriction of blood vessels
and subsequent death of the cells holding the hoof and coffin bone together. The take home message and exciting thing would
be to find a drug which could block the harmful effect of these enzymes.
The support structures in the laminae have been found
to contain molecules similar to those found in the joint cartilage. Perhaps the
use of drugs such as Hyaluronic Acid
(like Legend and Polyglycan) and Polysulfated Polyglycans (like Adequan) would
be of benefit in either preventing separation of the laminae, or in treating
the laminae and helping it recover quicker.
There is also some discussion about the use of cortisone during the acute phase of the
disease. Since cortisone is a very potent anti-inflammatory drug, it is
used frequently to reduce inflammation in many parts of the body. It is routinely
injected into arthritic joins with profound effects, as well as to reduce
swelling in the limbs with allergies or conditions as serious as lymphangitis
and pneumonia. Its use however has previously been discouraged with laminitis
due to the association with Cushings disease and Insulin Resistance. Perhaps if
low doses were given via regional limb
perfusion in an acute case, some of the swelling within the hoof capsule
could be prevented or reduced. If successful, this would dramatically reduce
pain and possibly improve the prognosis.
With a reduction of blood flow as a result of
inflammation, a decrease in glucose or energy may be more harmful to the
laminae than a decrease in oxygen. Previously, the thinking was that the
lamellar tissue was oxygen-starved with laminitis. Recent work however has
shown that the laminae don’t require oxygen to survive. They can survive using
what is known as anaerobic metabolism. While this information is fascinating,
its clinical application is unknown at this time.
It is unanimous
that cryo-therapy (icing of the lower leg or foot) is of benefit in treating
acute laminitis. Every one should be putting at risk cases (such as colic,
pneumonia, etc.) in ice or cooling the blood to the distal limb as soon as
possible. I recommend ice as long as they are at risk, or for 72 hours
continuously in an acute case or unknown origin.
Hopefully your horse will never suffer from laminitis.
However if you suspect a problem, or they are at risk, early aggressive treatments
may save their life.
Should you have any questions about laminitis or any
other condition or disease of the horse’s foot, please don’t hesitate to
contact me at rboswelldvm@aol.com.
Please leave your phone number as it may be easier for me to respond by calling
you directly.
In closing I would like to tell you how thankful I am
for your support, confidence and trust since starting my solo practice. Since
this will be my last letter before the holidays, I want to take this
opportunity to wish all of you and your families a very Merry Christmas and a
Happy New Year.
All the Best,
Rob Boswell, DVM