the 2007 Abstract Presentations - Wound Healing Society

Abstracts
126
ELECTROSPUN FIBRINOGEN AND FIBRIN NANOFIBERS
FOR ANGIOGENESIS IN VITRO
Tatjana Morton 1 , Lila Nikkola 2 , Nurredin Ashammakhi 2 , Susanne Wolbank 3 ,
Anja Peterbauer 1 , Martijn van Griensven 1 , Heinz Redl 1
1 Ludwig Boltzmann Institute for Experimental and Clinical Traumatology,
Vienna, Austria,
2 Tampere University of Technology, Institut of Biomaterials, Tampere,
Finland,
3 Red Cross Blood Transfusion Service of Upper, Linz, Austria
Introduction: Electrospinning has been recognized as an efficient technique for
the fabrication of polymer nanofibers. It uses an electric field to control the
deposition of polymer fibers onto a target substrate. This electrostatic processing
strategy can be used to fabricate fibrous polymer mats composed of fiber
diameter mostly between 100 nm and 3 mm. In this study, we describe electrospinning
of fibrinogen and fibrin nanofibers in an attempt to create biomimicking
tissue-like material in vitro for use as a tissue scaffold for angiogenesis.
Materials and Methods: We have used lyophilized human fibrinogen of the
product Tisseel s VH (Baxter AG, Austria) to demonstrate fibrinogen and
fibrin electrospinning. Fibrinogen dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol
and sodium chloride solution was electrospun under various conditions. To
create fibrin nanofibers a mixture of solved fibrinogen and thrombin was spun.
The quality of electrospun fibers were analyzed by scanning electron microscopy
(SEM) and gelelectrophoresis. For in vitro tests sterile matrices were
seeded with human adipose derived stem cells cultured in DMEM/Ham’s F-12
medium for 14 days.
Results and Discussion: Electrospun fibers of fibrionogen and fibrin were
processed for scanning electron microscopy (SEM) evaluation and analyzed
by native gelelectrophoresis. Because of their small diameters, fibers are more
attractive for cell attachment. Their similarity in size to native extracellular
matrix components and the 3-dimensional structure allows cells to attach to
several fibers in a more natural geometry. In addition seeded cells showed
different proliferation patterns on matrices containing growth factors in
comparison on nanofibers without additives. From the results of this study we
think that it may be possible to construct fibrous scaffoldings composed of
nanofibers for tissue engineering and wound repair using the process of
electrospinning with fibrinogen or fibrin. With the electrospinning process,
structures of various shapes and sizes can be constructed to get 3-dimensional
appropriate scaffolds for specific use.
127
AN EVALUATION OF HYPEROXYGENATED FATTY ACID
(HOFA) AND ITS EFFECTS ON THE MICROCIRCULATORY
AND BARRIER PROPERTIES OF THE SKIN
F. Muniz, D. Brett
Smith & Nephew Wound Management Division, Largo, FL, USA
Introduction: HOFA is a technology based on the introduction or saturation of
peroxides into fatty acid esters via the presence of ultraviolet light and
controlled temperatures. During the manufacturing process, oxygen is introduced
by bubbling oxygen through natural oils at a specific temperature over
time until the oil viscosity increases and the peroxide value is achieved. The use
of this product has been adopted as a method of preventing pressure ulcers and
treating circulatory insufficiencies. It is felt that this therapy is effective due to
the release of free oxygen thus promoting microcirculation at the site of
application. Improvements in local microcirculation, barrier properties, elasticity,
moisturization levels, etc., of the skin have provided clinical evidence to the
efficacy of HOFA.
Methods: Microcirculation evaluated via Laser Doppler, Transepidermal
Water Loss (TEWL) evaluated via Servo Med EP2 Evaporimeter and Moisturization
Value evaluated via Nova DPM 9003.
Results: Microcirculation –an increase of 28% microcirculation was achieved
after application of HOFA to skin. Transepidermal Water Loss (TEWL) - a
reduction of the TEWL was achieved after application of HOFA to skin.
Moisturization Value- an increase in the level of moisturization was achieved
after application HOFA to skin. Note: all data were generated against a control
of no HOFA treatment.
Discussion: Based upon a preliminary evaluation of the HOFA technology/
therapy, data shows evidence of a physical response to the application of
HOFA to the skin. As a result, an increase in microcirculation, moisturization
and a reduction of TEWL were noticed after application. This investigation
opens opportunities to further study the benefit of this technology/therapy as a
potential pressure ulcer prevention therapy as well as a therapy to improve the
barrier properties of the skin.
128
ULTRASTRUCTURAL LOCALIZATION OF INTEGRIN
SUBUNIT BETA 4 AND ALPHA 3 WITHIN THE MIGRATING
EPITHELIAL TONGUE OF IN VIVO HUMAN WOUNDS
Robert A. Underwood 1 , Marcia L. Usui 1 , William G. Carter 2,3 , John E.
Olerud 1
1 Department of Medicine (Dermatology), University of Washington, Seattle
WA, USA,
2 Department of Pathology, University of Washington, Seattle WA, USA,
3 Fred Hutchinson Cancer Research Center, Seattle WA, USA
Subsequent to wounding, keratinocytes must quickly restore barrier function.
In vitro wound models have served to elucidate many cellular mechanisms of
wound closure. To evaluate the roles of associated integrins alpha 6 beta 4 and
alpha 3 beta 1 in vivo, we used ultrathin cryomicrotomy to concomitantly
observe tissue ultrastructure and immunogold localization in unwounded skin
in 1 to 2 day human cutaneous wounds. Localization of the beta 4 integrin
subunit in unwounded skin shows expected dominant hemidesmosomal association
and minor lateral basal cell-cell expression. Beta 4 in the migrating
epithelial tongue localized to both lamellipodia and filopodia in juxtaposition
to wound matrix. Increased concentrations of beta 4 were found in cytoplasmic
vesicles within a subset of leading edge keratinocytes. The alpha 3 integrin
subunit showed strong association with filopodia but not lamellipodia, and was
dominantly localized to basal lateral cell-cell junctions in unwounded skin and
both cell-cell and cell-matrix interactions in wounded skin. In vivo ultrastructural
localization of integrin subunits beta 4 and alpha 3 supports the
hypothesis, based on in vitro studies, that beta 4 has a multifunctional
involvement in stable adhesion and transient adhesion within actin rich
lamellipodia and filopodia and may follow a different endosomal trafficking
pathway than the alpha 3 integrin subunit. George F. Odland Endowed
Research Fund, NIH DK 59221, NIH EB 004422, NSF EEC 9529161
[University of Washington Egineered Biomaterials (UWEB)].
129
CXCR3 / MICE DISPLAY A DYSFUNCTION IN
BASEMENT MEMBRANE REMODELING AND DELAY IN
RE-EPITHELIALIZATION DURING WOUND HEALING.
Diana Whaley, Cecelia C. Yates, Wayne W. Hancock, Bao Lu, Joseph
Newsome, Patricia A. Hebda, Alan Wells
Department of Pathology and Otolaryngology, University of Pittsburgh and
Pittsburgh VAMC
Wound healing results from a complex and dynamic series of biological events
that require several growth factors, chemokines and matrix components to
signal in a synchronize manner. We have found that this process is at least in
part mediated by ELR-negative chemokines acting through the common
receptor CXCR3. We have previously shown that in the absence of CXCR3
signaling, full thickness excisional wounds exhibited a significant delay in
dermal healing, poor remodeling, and diminished reorganization of collagen
that impacted the dermal strength. However, the status of dermal maturation
communicates with epidermal healing.
To examine CXCR3 role in re-epithelialization and the re-establishment of the
dividing basement membrane in wound repair, full thickness excisional wounds
were created on CXCR3 wild type (1/1) and knockout ( / ) mice. Wounds
were histologically analyzed for re-epithelialization at various days postwounding.
Production of extracellular matrix components such as laminin, Type IV
collagen, fibronectin, and tenascin, involved in formation of basement membrane,
was analyzed immunohistochemically at days 7, 14, 21, 30, 60, and 90
postwounding. We have demonstrated that the loss of CXCR3 signal not only
results in a delay in the re-epithelialization process but an altered expression of
many key basement membrane components implicated in wound repair. These
results suggest that CXCR3 and its ligands may play an important role in
directing the reconstruction of the basement membrane and modulates reepithelialization.
These studies further establish the emerging signaling network
that involves the CXCR3 chemokine receptor and it ligands as a major
regulator of wound repair.
These studies were supported by grants from the National Institute of General
Medical Science of the National Institutes of Health (USA).
A48
Wound Rep Reg (2007) 15 A14–A54 c 2007 by the Wound Healing Society