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Kanevsky et al. Stretch device for scar therapy

time (total of 20 min per day) used in our study are humans. This study evaluated end-points correlating
both less when compared to other studies where to the early remodeling phase of wound healing,
skin was stretched continuously for long periods of offering assessment of fibrosis but not long-term scar
time under higher tension. [22-24,37] In these studies remodeling. Despite these differences, there still
prolonged tissue stretch under high tension caused remain substantial similarities between the underlying
release of inflammatory mediators that promoted wound healing physiology, providing promise for the
scar formation. [24,38] Although such previous studies utility of this device. However, future experiments are
have demonstrated tissue stretch can induce scar still planned to measure the effects of the device long
formation, the discussion on timing, force and term on scarring. These studies, also proposed in
duration of stretch required to induce a scar remains mice, will also allow for more extensive biochemical
unclear. [22-24,38] The results from the 2× stretch group assessment of the device by measuring parameters
in the present study provides some support for the associated with mechanotransduction, including
detrimental effects of high-tension tissue stretch, focal adhesion kinase levels to better describe the
where scars in this group were comparable to underlying mechanism of the observed reduction
controls (non-stretched scars). In addition to worse in fibrosis. Additionally, further quantitative analysis
appearing scars, the 2× group also had more collagen of the number of fibroblasts in numerous sections,
deposition in the dermis, and higher levels of TGF-β1. thickness of the scars and the epidermal thickness
Compared to the favorable scar results in the 0.5× would have added to the analysis of scar reduction.
and 1× groups, the latter data suggests that there
is a threshold of tension, above which tissue stretch To further elaborate the elegant mechanisms at
promotes scar formation and below which tissue work in the modulation of scar formation the authors
stretch may decrease scar formation. plan to evaluate the device in a skin scarring animal
model more indicative of human scar biology, such
Substantial evidence describes the role of mechano- as the red Duroc pig. [33] While this study provides
transduction in scar formation. Our study builds substantial promise for the device presented here,
on preliminary findings that controlling tension in a subsequent studies will establish more precisely the
proliferating scar modulates production of extracellular optimal vector, force, and duration of tissue stretch
matrix proteins. Langevin et al. [26-28,35] described needed to effectively and consistently reduce scar
several cellular and extracellular matrix changes formation. Optimizing such parameters may permit
that take place once skin is stretched that promote the development of a novel scar treatment device that
decreased scar formation. Tissue stretch causes could be used to treat a wide variety of scars.
fibroblast cell spreading, cytoskeletal and nuclear
remodeling, decreased type 1 collagen production and Scar formation has detrimental effects on social,
decreased production of TGF-β1. A recent paper by psychological, and physical function. [1-5] Current scar
Suarez et al. [37] describes the role of tension in keloid therapies are poorly understood and insufficient to
pathology, specifically tension dependent proteins: insure optimal scar formation. In one promising study,
Hsp27, α2β1-Integrin, and PAI-2. Furthermore, the Lim et al. [39] showed in a randomized clinical trial that
clinical correlation of reduced fibrosis associated with their Embrace device, which differs significantly from
intermittent parallel longitudinal tension and significant the device used in this study, managed to achieve
improvements in scar appearance using parallel scar statistically significant results. The Embrace device
massage offers further support for the clinical utility of reduces perpendicular tension by direct opposition
the device presented herein. This suggests that tissue rather than by application of parallel stretch described
stretch induces mechanical signals that may regulate in this study. The device presented herein, applied
gene expression and overall function of fibroblasts. only intermittently rather than continuously as is the
Embrace device, appears to function similarly in that
It is important to note that this study is not without it ultimately opposes the wound edges. The present
limitations. A murine model was used as a preliminary device is only in its infancy, and further investigations
means to evaluate the efficacy of this novel device of the optimal time interval of use, vector of stretch,
in modulating scar formation during the proliferative and magnitude of stretch provide hope for an effective
phase of wound healing. The cost and previous use treatment strategy for the reduction of scar formation.
of a murine model to study wound healing made
mice a logical first choice of animal model for this In conclusion, in this study we designed and manufactured
investigation. Mouse skin is significantly different a device that may provide parallel tissue stretch to a
from human skin in elasticity and healing potential, wound in order to improve scar formation. Our results
limiting the direct translation of these findings to show that the 1× strength device is overall superior
356 Plastic and Aesthetic Research ¦ Volume 3 ¦ November 15, 2016