Wound healing and management is a challenge

Scientific Communication
The value of veterinary wound
management for human wounds
and wound care
THE FIRST IN A SERIES: There remains much to learn
about the science of wound healing in humans. It may
be possible to improve our understanding of wound
healing by looking to other disciplines. Veterinary wound
healing research has something to offer and this article
Wound healing and management is a challenge
not only in human medicine but also in veterinary medicine. The struggles to heal complicated
wounds in companion animal species are strikingly similar to those in human patients despite
major differences between species. A comparison
of the similarities in healing between species may
identify new mammalian wound models with
a much higher concordance rate, and a critical
analysis of the differences may contribute to the
common good. Sharing clinical problems, treatments, research, models, and ideas between human and veterinary experts can therefore benefit
both human and veterinary wound healing and
management, which speaks for an intensified collaboration between human and veterinary wound
healing associations.
Animal wound models
Although the majority of animal
models in wound healing resear ch
are based on rodents, the concordance rate between rodents and humans is only 53%, which suggests
that results from rodent models
are not likely to translate into improved clinical outcomes. A lack of
concordance is not surprising given
the anatomical, physiological, and
immunological differences between
rodents and humans1. For example;
2014 VOL 14 NO 2
adrid · Spain
Submitted to the EWMA
Journal, based on a presentation given a EWMA
symposium (VWHA/EWMA
Symposium on Veterinary
Wound Management and
Antimicrobial Resistance:
Animal Wound Care - Best
practice and new knowledge) at the EWMA ·
GNEAUPP 2014, Madrid.
appears in the EWMA Journal as the first in a series
of articles that looks outside of the traditional topics
covered. We hope that you enjoy learning about wound
healing in another species and will gain a better understanding of the similarities that exist.
the contribution of wound contraction and
epithelialisation to second intention healing of
cutaneous wounds varies significantly across species due to differences in the gross and histologic
structure of the skin. Rapid contraction is a common feature of loose skin, which is present in the
body/trunk of most companion animals, including horses, dogs, and cats. In contrast, extremity
wounds in these animals heal in a manner more
similar to wounds in tight-skinned species (e.g.,
humans and porcines), primarily as the result of
re-epithelialisation2. Limb wounds in horses and
human leg wounds heal in a similar way: healing
in both species occurs mainly through epithelialisation with only limited wound contraction
(Table 1, Fig. 1).
Jacintha M. Wilmink
Diplomate RNVA
Veterinary Wound
Healing Association
Past President and
Council Member
[email protected]
Conflicts of interest:
Table 1: Comparative cutaneous wound healing across species.
Scientific Communication
Figure 1: An example of a horse limb wound
that has healed almost completely by epithelialisation.
Figure 2: An example of a horse limb wound
with unhealthy granulation tissue, necrotic
parts, and biofilm formation, which most
likely is subject to chronic inflammation.
Some excess granulation tissue has already
Differences between human and equine patients and
At first glance, human and equine patients do not seem
to have much in common, and their wounds seem very
different. Human patients are often elderly and sometimes
obese or with nutritional deficiencies. Many human patients suffer from systemic diseases that lead to vascular,
diabetic, or pressure ulcers. These ulcers occur gradually
with the progression of the disease, must heal by second
intention, and often develop into chronic, difficult to heal
wounds. In contrast, equine patients are usually less than
3 years of age and in normal nutritional condition. Their
wounds are the result of sudden trauma, and the aim of
treatment is primary intention healing. Not all wounds
can be sutured, however, and wound dehiscence occurs
frequently, which means that many wounds must heal by
second intention and can develop into chronic, difficult
to heal wounds.
Similarities between human and equine wounds
Although human and equine patients and wounds are
Figure 3: Fibroproliferative disorders in the
This horse exhibits EGT in the central part of
the wound, hypertrophic scarring along the
wound margins, congestion, edema, and fibrosis in the tissues around the wound and
distal limb.
initially very different, both species can suffer strikingly
similar problems with second intention healing. It is close
to normal for the limb wounds of horses to form unhealthy
granulation tissue that is covered in biofilm and subject
to chronic inflammation (Fig. 2). In contrast to human
wounds, that often have a lack of granulation tissue, exuberant granulation tissue (EGT) is a regular complication
in horse wounds (Fig. 3). The clinical presentation of EGT
is similar to that of human keloids, except that equine
EGT is not epithelialised. Horse limb wounds sometimes
develop scars that look like keloids, but histology shows
that these are hypertrophic scars rather than true keloids.
Horses, but not ponies, have a genetic predisposition for
developing EGT and hypertrophic scars. Likewise, a genetic susceptibility to keloid formation has been observed
in humans. Similarities in the histological appearance and
dysregulated cytokine profiles of these fibroproliferative
disorders in horses and humans have been shown3.
Another similarity between humans and equines is the
hypoxia of wounds. In horses, wound hypoxia is caused
by the anatomy of the limbs, which have only 2 main
arteries running to the distal limb and limited collateral
alternatives. When a horse limb is injured, the perfusion
of the wound and the distal part of the limb can be dam-
2014 VOL 14 NO 2
aged, both by vessels that are cut and/or obstructed by
clots or by the swelling of the tissues as a reaction to the
traumatic incident. Equine wounds can therefore suffer
from impaired oxygenation as well as problems with the
venous return, which can lead to congestion, oedema, and
finally to fibrosis (Fig. 3).
The final similarity between human and equine wounds
is the susceptibility of limb wounds to the development
of pressure sores. Equine pressure sores occur due to treatment with bandages or casts. The causes are the same as
those that are known in humans: the amount of pressure,
the duration of time in which the pressure is present, and
shearing forces. A similar division in the severity and depth
of pressure sores or ulcers can be made in equine and
Comparative physiology
It has been shown that within the equine species horses
heal much slower and with more complications than ponies. By comparing many aspects of the physiology of
wound healing between these sub-species, it has been
determined that most of the differences in clinical healing can be explained by the course of the inflammatory
response and the capacity of leucocytes to produce inflammatory mediators. This knowledge has resulted in
enormous improvement in clinical treatment strategies.
EWMA 2015
13 -15 MAY 2015
in London
The EWMA UCM programme offers students of wound
management from institutes of higher education across Europe
the opportunity to take part of their academic studies whilst
participating in the EWMA Conference.
The opportunity of participating in the EWMA UCM is available
to all teaching institutions with wound management courses for
health professionals.
The UCM programme at the EWMA 2015 Conference
in London will offer networking opportunities between the
students from various UCM groups, UCM Lectures as well as
assignments and workshops arranged specifically for the
UCM students.
EWMA strongly encourages teaching institutions and students
from all countries to benefit from the possibilities of international networking and access to lectures by many of the most
experienced wound management experts in the world.
Yours sincerely
Comparing the (patho)physiology of human and equine
wounds may also reveal new elements of wound healing and wound management. The similarities in the
epithelialisation/contraction ratio, the development of
fibroproliferative disorders, biofilm formation, chronic
inflammation, dysregulated cytokine profiles, hypoxia, and
problems with pressure may introduce some promising
modeling alternatives to consider. In addition, naturally
occurring horse wounds may be useful for clinical trials
because neither equine nor human wounds can be easily
mimicked in experimental set-ups. The correlation between human and equine wounds may lead to the development of new insights and treatments for both species.
We conclude that further collaborations between human
and veterinary experts in wound healing and management
will be of benefit to both fields.
Dubravko Huljev
Chair of the Education Committee
Participating institutions:
Donau Universität Krems
Haute École de Santé
Geneva, Switzerland
HUB Brussels
Lithuanian University of Health Sciences
University of Hertfordshire
United Kingdom
Universidade Católica Portuguesa
Porto, Portugal
1. Special Section Wound Repair and Regeneration: Wound healing in Veterinary
Medicine; Asking the right questions to find the keys to wound healing. WRR
2. Volk SW and Bohling MW. Comparative wound healing- Are the small animal
veterinarian’s clinical patients an improved translational model for human wound
healing research? WRR. 2013;21:372-81
3. Theoret CL and Wilmink JM. Aberrant wound healing in the horse: naturally
occurring conditions reminiscent of those observed in man. WRR. 2013;21:365-71.
For further information about the EWMA UCM, please visit
the Education section of the EWMA website www.ewma.org
or contact the EWMA Secretariat at [email protected]
2014 VOL 14 NO 2
VeraFlo Therapy
V.A.C.Ulta™ Negative Pressure
Wound Therapy System:
more granulation
In a porcine study comparing
V.A.C.® Therapy to VeraFlo™ Therapy
with saline, there was 43%* more
granulation after 7 days
of therapy.
VeraFlo™ Therapy can help Cleanse, Treat and Heal by combining the
benefits of V.A.C.® Therapy with automated solution distribution, dwell and removal.
Cellulose acetate
mesh, coated with
soft tack silicone
It is also suitable for use, under medical
supervision, with NEGATIVE PRESSURE
* Results have not yet been confirmed in humans. Lessing MC, et al. Negative Pressure Wound Therapy With Controlled Saline Instillation (NPWTi): Dressing Properties and Granulation Response In Vivo.
Wounds 2011; 23:309-319.
NOTE: Specific indications, contraindications, warnings, precautions and safety information exist for KCI and Systagenix products and therapies. Please consult a physician and product instructions
for use prior to application. This material is intended for healthcare professionals.
© 2014 KCI Licensing, Inc. All rights reserved. All trademarks designated herein are proprietary to KCI Licensing, Inc., its affiliates and/or licensors. DSL#14-0456.SYX4326.EWMA (9/14)