8/4/2019 NWHS: Equine Wellness Stem Cells and Beyond

1/2October 2011 The Northwest Horse Source www.nwhorsesource.com

Over the last several years, horse owners have been exposed

to many new treatment options for soft-tissue and joint

injuries in their horses along with the often-confusing

terminology that accompanies these new therapies: Stem cells,

platelet-rich plasma (PRP) and IRAP (interleukin-1 receptor antago-

nist protein). These treatments plus others fall under the umbrella

of regenerative medicine.

Equine veterinarians, including the doctors at Pilchuck

Veterinary Hospital, have used regenerative therapies for severalyears now to treat horses suffering from a number of conditions,

including soft-tissue injuries and arthritis. The power of regen-

erative medicine is that it can give horses a second chance after

an injury, many times aiding in the quality of the healing and

decreasing risk of recurrence.

Regenerative medicine involves using the bodys own cells

to repair or replace damaged tissues. Goals include: healing the

damaged tissue in an organized manner, ideally without scarring;

preserving function; and approximating what the original tissue

was like (e.g., same strength and elasticity). If healing doesnt occur

in an organized way, the new tissue wont be as strong or resilient

as the original, making the horse vulnerable to re-injury or failure

in repair of the damaged tissue.

Stem cell therapyStem cell therapy has been used successfully to treat equine

injuries involving tendons, ligaments and joints. Because embry-

onic stem cells (which come from a fetus or placental membrane)

are difficult to obtain due to medical and ethical reasons, veteri-

narians began to use bone marrow as a source for undifferentiated

cells. These cells are capable of maturing into a variety of cell types

once out of the marrow space and under the influence of the local

tissue environment, just like embryonic stem cells.

In the horse, we have two viable sites for harvesting cells: fat

from the tail head region and directly from the bone marrow.In both cases, samples of cells are collected and sent to a labora-

tory where the cells are cultured to produce a large number of

viable cells. The cells are then returned frozen on ice and can

be implanted.

Another process involves concentrating the cell aspirates

from either the bone marrow or fat. Cells from either location

are harvested, then concentrated with a special centrifuge and

injected directly into the site of injury.

The decision to use fat-derived cells, bone marrow cultured

stem cells, or bone marrow aspirate concentrate is often based on

clinician preference, the type of injury and the timing of when you

want the cells in place. Pilchuck Veterinary Hospital clinicians tend

to use bone marrow-derived techniques.

In tendon or ligament injuries, veterinarians are applying

regenerative medicine therapies to horses with chronic injuries

(especially in the suspensory ligament) and in acute core lesion

injuries of the flexor tendons and suspensory ligament. The goal i

to create an enhanced environment for healing and to provide cell

that can form better collagen, which improves tendon or ligamenfiber alignment. With improved healing, the likelihood of injury

recurrence is decreased.

Stem Cells and Beyond

By: Dr. James Bryant, DVM, Diplomate ACVS

REGULAR FEATURE Equine Wellness

Healing Horses with Regenerative Medicine

Tendon pre-injection and tendon 2 weeks post injection.

8/4/2019 NWHS: Equine Wellness Stem Cells and Beyond

2/2www.nwhorsesource.com The Northwest Horse Source October 201

An additional application of stem cells is in the joints of horses.

Recent studies suggest an improved outcome in horses with soft-

tissue injuries (specifically meniscal ligament) in the stifle joint.

PRPThe use of platelet-rich plasma for treating soft-tissue tendon

and ligament injuries is rapidly expanding, and is sometimes used

in combination with stem cell therapy. The smallest blood cells,

platelets are responsible for clotting and are the first respondersto an injury. PRP therapy works by delivering a high concentration

of platelets to the injured site, increasing the amount of growth

factors and helping the injury to heal. PRP is created by spinning

the horses whole blood in a high-speed centrifuge, eliminating the

red and white blood cells and leaving a high concentration of plate-

lets in the serum. The veterinarian then injects the plasma directly

into the lesion to aid in healing. Recently applications in the joint

are also being used.

IRAPTechnically, IRAP (or interleukin-1 receptor antagonist protein)

isnt a regenerative therapy, but is often grouped with stem cell andPRP treatments.

IRAP therapy works by blocking interleukin-1, which causes

inflammation and is naturally released from the body after an

injury. Veterinarians collect blood from the horse and incubate it

in the presence of chromium-coated beads, which amplify IRAP

production.

IRAP is most commonly used as a joint therapy in horses for

the treatment of synovitis and early arthritis. Post-joint surgery

patients are also excellent candidates for IRAP. IRAP is especially

exciting due to its potential for addressing osteoarthritis, one of the

main causes of lameness in horses.

ConclusionCase selection is critical for a successful outcome; regenerative

medicine is not always the most appropriate therapy. Discuss treat-

ment options with your horses veterinarian, taking into account

the horses prognosis, the cost of different regenerative techniques,

the rehabilitation requirements post-therapy, and your goals for

the horse.

Regenerative medicine is still young and holds an exciting

future. Horses have been one of the first animals to benefit from

these techniques, and as new research is conducted and break-

throughs occur, we are likely to see even more effective healing

applications for our equine friends and athletes.

Pilchuck Veterinary Hospital offers a variety of regen-erative medicine techniques, including those described above:

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