the 2007 Abstract Presentations - Wound Healing Society

Abstracts
41
BFGF GENE TRANSFER BY ADENO-ASSOCIATED VIRAL 2
VECTORS DECREASES WORK OF ACTIVE DIGITAL
FLEXION AND ADHESION FORMATION: AN IN VIVO
STUDY UP TO END TENDON HEALING STAGE
Yi Cao, MD, Bei Zhu, MD, Ke-Qin Xin, MD, PhD, Xiao Tian Wang, MD,
Paul Y. Liu, MD, Jin Bo Tang MD
Department of Hand Surgery, Nantong University, China, Roger Williams
Hospital, Providence, RI
Purpose: Previously, we demonstrated that adeno-associated virus-2 (AAV2)
mediated gene transfer promotes expression of collagen genes associated with
tendon healing process in tenocytes and enhanced healing strength at 4 weeks
post-surgery. In this study, we propose to investigate effects of delivery of the
bFGF gene to injured flexor tendon in a clinically relevant injury model on
several ultimate outcome measures at end tendon healing stage—ultimate
gliding function, work of active digital flexion and extent of matured adhesions.
Methods: We used 20 long toes from 10 white leghorn chickens. These toes
were randomly divided into 2 groups of 10 each. The flexor digitorum
profundus (FDP) tendons were cut completely in zone 2 and were repaired
with modified Kessler method. In AAV2-bFGF group, a total of 2 10 9
particles of AAV2 harboring the bFGF gene were injected to both stumps of
the cut tendon ends before repair. In non-treatment group, the tendons were
repaired by the same method, but no injection was given. The operated toes
were immobilized in semiflexion position over initial 3 weeks and were released
to allow free motion thereafter. At the end of 12 weeks, the toes were harvested
and the energyrequired to actively flex the toe (work of flexion) was tested in a
tensile testing machine (Instron). Gliding excursion of the repaired FDP tendon
was measured under a load of 10 N. The extent of peritendinous adhesions was
recorded according to scoring criteria.
Results: The work of flexion of the toes in the AAV2-bFGF treatment group
(0.021 0.006 J) was significantly less than that of non-treatment controls
(0.033 0.015 J) (p o 0.05). The gliding excursion of the AAV2-bFGF treated
FDP tendons was not significantly changed compared with that of the tendons in
non-treatment group. Adhesion scores of the AAV2-bFGF group (2.8 0.7 points)
were significantly less than those of the control tendons (3.8 0.9 points) (p o 0.05).
Conclusions: bFGF gene transfer via AAV2 vectors to digital flexor tendon
significantly decreases energy required to flex the digits and adhesion formations.
We evaluated the outcomes at the end stage when adhesions and healing
had matured and function was steady. These findings suggest that delivery of
bFGF gene through AAV2 has advantage of decreasing adhesion formation
during tendon healing process and benefits ultimate digital motion.
42
FIBROBLAST GROWTH FACTOR-2 IMPROVES THE
QUALITY OF LOWER EXTREMITY WOUND HEALING
Sadanori Akita 1 , Kozo Akino 2 , Akiyoshi Hirano 1
1 Dept. of Plastic Surgery, Nagasaki University,
2 Dept. of Neuroanatomy, Nagasaki University
The reconstruction of lower extremity is difficult when the patients are elderly
and with severe basic diseases such as cardiac, metabolic and vascular diseases.
Fibroblast growth factor-2 (FGF-2) is a stimulator of the quality of wound
healing in 3 rd and 2 nd degree burn wounds as well as a potent angiogenic factor.
On the other hand, there are more clinical merits of using an artificial dermis for
promoting wound bed preparation in difficult wound healing of the lower
extremities. We previously demonstrated the successful serial artificial dermis
and secondary thin split-thickness skin grafting. Here the combination of FGF-2
and artificial dermis with secondary split-thickness skin grafting was subjected to
historical comparative analysis with similar age, follow-up period and duration
to and thickness of the secondary skin. The average age of 66.5 years of 12
patients with at least half a year of post-complete healing (2.0 0.8 years) was
used daily FGF-2 at 1 m g/cm 2 until secondary skin grafting. The skin hardness
demonstrated by a durometer (TECLOCK, Co., Ltd, Nagano, Japan) was
significantly less hard in FGF-treated scars than in non-FGF-2 treatment
(16.2 3.8 vs. 29.2 4.9, P o 0.01). The corneal layer (stratum corneum)
parameters indicated by effective contact coefficient, transepidermal water loss
(TEWL), water content and thickness were all significantly greater in non-FGFs
treatment than in FGF-2 treatment detected by a transportable moisture meter
(ASA-M2, Asahi Biomed, Co., Ltd, Yokohama, Japan) (contact coefficient;
10.9 1.05%, 17.9 1.95%, p o 0.01, TEWL; 13.2 2.16 g/m 2 /h, 21.2 2.93 g/
m 2 /h, p o 0.01, water content; 24.7 5.06 mS, 46.0 5.67 mS, p o 0.01, thickness;
12.1 3.14 mm, 17.2 1.87 mm, p o 0.01, FGF-2 treated, non-FGF-2
treated, respectively). These results suggest that daily FGF-2 treatment until
immediately before secondary split-thickness skin grafting demonstrates better
quality of wound healing in term of hardness and corneal barrier function.
43
CELL BIOLOGY AND MOLECULAR MECHANISMS OF
INSULIN-INDUCED ACCELERATION OF HEALING
Yan Liu, Min Yao
Manuela Martins-Green Department of Cell Biology and Neuroscience,
University of California, Riverside, CA 92521
As a dynamic, interactive and complex process, wound healing involves
inflammation, granulation tissue formation, re-epithelialization and tissue
remodeling. Governed by the local production of cytokines and growth factors,
keratinocytes and endothelial cells proliferate, migrate and differentiate to
achieve re-epithelialization and angiogenesis respectively. We have investigated
the topical application of insulin and find that it significantly enhances the
wound healing process in vivo. To determine the cell and molecular basis of
insulin acceleration of healing, we studied the effects of this protein on
keratinocytes and endothelial cells (EC). Insulin stimulates keratinocyte proliferation
and migration in a dose- and time-dependent manner and it does so
independently of EGF/EGFR. This stimulation is dependent on activation of
Akt, PI-3 K and sterol regulatory element binding proteins (SREBPs). The
effect of insulin on EC results in stimulation of EC migration but does not affect
proliferation and the effect on migration is independent of VEGF. In EC,
insulin stimulates phosphorylation of Akt and ERK1/2 in a dose- and timedependent
manner, but only Akt is involved in the effect of insulin on EC
migration. Furthermore, phosphorylation of Akt induced by insulin decreases
when cells are pre-treated with VEGFR inhibitor SU1498. Our results show
that PI3K- Akt- SREBP are critical molecules in insulin stimulation of
keratinocyte migration/proliferation and in EC migration. Taken together,
these results show that insulin is another factor that accelerates wound healing
and hence it should be given high consideration as potential treatment for
impaired wounds.
44
THE USE OF RECOMBINANT HUMAN EPIDERMAL
GROWTH FACTOR (RH-EGF) TO PROMOTE HEALING FOR
CHRONIC RADIATION ULCER
Sang Wook Lee 1 , MD PhD, Sue Young Moon 1 , MS, Yeun Hwa Kim, MS,
Joon Pio Hong, MD PhD, MS
Asan Medical Center Univcersity of Ulsan Department of Radiation Oncology
and Plastic Surgery
Purpose: Along with in vitro studies, this case report describes the first
successful use of recombinant human epidermal growth factor (rh-EGF) in
radiation induced chronic wound of bone and skin.
Method: Human fibroblasts were primarily cultured and were divided into two
major groups. The non-radiated group was then divided into 5 subgroups;
control and treated with various doses of rhEGF (1 nM, 10 nM, 100 nM, and
1000 nM). The radiated group underwent radiation with 4MV energy therapeutic
linear accelerator (CLINAC 600C, Varian, Palo Alto, CA, USA) at dose
rate of 2 Gy/minute totaling 4 Gy then divided into 5 subgroups; control and
treated with various doses of rhEGF (1.6 nM, 16 nM, 160 nM, 1600 nM). The
cells were then evaluated: 1) MTT assay from day 2 to 7; 2) FACscan was used
to evaluate the change in cell cycle. As a case study, a 59-year-old female is
presented with a radiation induced ulceration of the chest lasting 3 years
underwent treatment with rh-EGF (Epidermin, Daewoong pharmaceuticals,
Seoul, Korea) with consent.
Result: The results revealed increased numbers of fibroblasts in all subgroups
of radiated group treated with rhEGF compared to the control. Cell count at
day 7 showed increasing tendency relative to the dosage and the highest increase
of 50% was seen in subgroup treated with 160 nm rhEGF (p o 0.05). The
subgroups treated with 1600 nM demonstrated decrease in cell count. Similar
tendency was seen in the nonradiated group where 100 nM rhEGF treated
subgroups showed the highest increase (p o 0.05). The results of the FACscan
showed increase in the S-phase of the cell cycle. In the patient, treatment with
rh-EGF and advanced wound care achieved healing within 16 weeks.
Conclusion: Rh-EGF in treatment against radiation induced ulcer may have
some promising potentials but further study is warranted. Fianacial support:
This study was performed with partial grant from Daewoong Pharmaceutical,
Seoul, Korea.
Wound Rep Reg (2007) 15 A14–A54 c 2007 by the Wound Healing Society
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