Human decellularized dermal matrix seeded with adipose-derived stem cells enhances wound healing in a murine model : experimental study

Objective: Full-thickness cutaneous wounds treated with split-thickness skin grafts often result in unaesthetic and hypertrophic scars. Dermal substitutes are currently used together with skin grafts in a single treatment to reconstruct the dermal layer of the skin, resulting in improved quality of scars. Adipose-derived stem cells (ASCs) have been described to enhance wound healing through structural and humoral mechanisms. In this study, we investigate the compatibility of xenogen-free isolated human ASCs seeded on human acellular dermal matrix (Glyaderm (R)) in a murine immunodeficient wound model. Methods: Adipose tissue was obtained from abdominal liposuction, and stromal cells were isolated mechanically and cultured xenogen-free in autologous plasma-supplemented medium. Glyaderm (R) discs were seeded with EGFP-transduced ASCs, and implanted on 8 mm full-thickness dorsal wounds in an immunodeficient murine model, in comparison to standard Glyaderm (R) discs. Re-epithelialization rate, granulation thickness and vascularity were assessed by histology on days 3, 7 and 12. Statistical analysis was conducted using the Wilcoxon signed-rank test. EGFP-staining allowed for tracking of the ASCs in vivo. Hypoxic culture of the ASCs was performed to evaluate cytokine production. Results: ASCs were characterized with flowcytometric analysis and differentiation assay. EGFP-tranduction resulted in 95% positive cells after sorting. Re-epithelialization in the ASC-seeded Glyaderm (R) side was significantly increased, resulting in complete wound healing in 12 days. Granulation thickness and vascularization were significantly increased during early wound healing. EGFP-ASCs could be retrieved by immunohistochemistry in the granulation tissue in early wound healing, and lining vascular structures in later stages. Conclusion: Glyaderm (R) is an effective carrier to deliver ASCs in full-thickness wounds. ASC-seeded Glyaderm (R) significantly enhances wound healing compared to standard Glyaderm (R). The results of this study encourage clinical trials for treatment of full-thickness skin defects. Furthermore, xenogen-free isolation and autologous plasma-augmented culture expansion of ASCs, combined with the existing clinical experience with Glyaderm (R), aid in simplifying the necessary procedures in a GMP-laboratory setting

Ways to increase precision and accuracy of wound area measurement using smart devices: Advanced app Planimator

<div><p>Introduction</p><p>Wound surface area measurement is important as therapeutic decisions may depend on the change of wound surface area over time. Digital planimetry is a popular technique in wound area measurement. It is accurate and repeatable when calibration is performed with 2 rulers placed at opposite sides of a wound. The aim of the current study was improving accuracy and precision of wound area measurement using capabilities of smart devices.</p><p>Methods</p><p>The correction of area measurement based on calculated camera tilt angle and the calculation of calibration coefficient of linear dimensions as weighted average were proposed. These and other improvements were applied in the Planimator app for Android, which was then used in the study. Accuracy and precision of the Planimator app were compared to the Visitrak device, the SilhouetteMobile device, the AreaMe software, and to the digital planimetry based on 2-ruler calibration with pictures taken by the smartphone, compact, and D-SLR cameras. Areas of 40 wound shapes of area ranged from 0.14 to 31.72 cm² were measured with each device. Medians of relative errors (REs) were compared in the accuracy tests and standard deviations (SDs) of relative differences (RDs) were compared in the tests of precision.</p><p>Results</p><p>The median of REs for the Planimator app was not significantly different from the medians of REs for the digital planimetry based on pictures from the compact or D-SLR cameras, but it was significantly lower than the medians of REs for the Visitrak and SilhouetteMobile devices, the AreaMe software and the digital planimetry based on pictures from a smartphone camera. The SD of RDs for the Planimator app was not significantly different from the SDs of RDs for the digital planimetry based on pictures from the compact or D-SLR cameras, but it was significantly lower than the SDs of RDs for the Visitrak and SilhouetteMobile devices, the AreaMe software and the digital planimetry based on pictures from a smartphone camera. The Planimator app installed at a smartphone revealed to be 2-fold more accurate and 1.5-fold more precise than the measurements with using ImageJ software based on pictures taken with the same smartphone.</p><p>Conclusions</p><p>The Planimator app occurred to have the same accuracy and precision as measurements with digital planimetry with 2-ruler calibration and based on pictures from a compact camera or a D-SLR camera. This app showed better accuracy and precision than the Visitrak and SilhouetteMobile devices, the AreaMe software and the digital planimetry based on pictures from a smartphone camera.</p></div

RDs of mean of measured area and the true value for 5 tilt angles of camera for the correction switched on or off.

<p><i>P</i>-values are given from the <i>t</i>-test for comparison the sample mean to the true value. Means were calculated from 12 measurements at each angle. Data necessary for the RDs calculations are given in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0192485#pone.0192485.s002" target="_blank">S2 Table</a>.</p

The relationship between the distance from camera and the calibration coefficient <i>k</i> for Samsung Galaxy S4 smartphone.

<p>The relationship between the distance from camera and the calibration coefficient <i>k</i> for Samsung Galaxy S4 smartphone.</p

Ways to increase precision and accuracy of wound area measurement using smart devices: Advanced app Planimator - Fig 3

<p><b>Height <i>h</i></b>_{<b><i>0</i></b>}<b>of an observed object is correctly reproduced at the picture when it is observed at the right angle (upper view).</b> In the case when there is a deviation from the right angle by the angle <i>α</i>, the reproduced height <i>h</i> of the object is smaller than <i>h</i>_<i>0</i> (lower view).</p

Standard deviations (SDs) and ranges of relative differences (RDs) for the Planimator app and other methods or devices used in the comparison.

<p>Data necessary for the REs calculations are given in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0192485#pone.0192485.s001" target="_blank">S1 Table</a>.</p

A wound shape with a marked small area and the center of gravity of this shape.

<p>The small area is at a distance <i>y</i>_<i>1</i> from the line segment <i>a</i>, and at a distance <i>y</i>_<i>2</i> from the line segment b. The center of gravity is at a distance <i>y</i>_<i>a</i> from the line segment <i>a</i>, and at a distance <i>y</i>_<i>b</i> from the line segment b. These line segments are used for calculation the calibration coefficients <i>k</i>_<i>a</i> and <i>k</i>_<i>b</i> as number of pixels per 1 cm at ruler A and B, respectively.</p