Skin substitutes are increasingly being used in the treatment of difficult to heal wounds but their mechanisms of action are largely unknown. In this study, using histology, immunostaining, flow cytometry, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction, we determined the response to injury of a human bilayered skin substitute. Meshing or scalpel fenestration of the construct was found to stimulate keratinocyte migration and to decrease proliferation. By 24 h, flow cytometry of the keratinocyte component showed that meshing was associated with a 33% decrease in the number of cells in S phase (p < 0.01). An approximately 2-fold decrease in staining for Ki67, a proliferation marker, was observed with meshing of human bilayered skin substitute. The process of reepithelialization was apparent by 12 h, however, the wounded human bilayered skin substitute was healed by day 3, and a stratum corneum and fully stratified epithelium were re-established by day 4. Reverse transcription polymerase chain reaction analysis and enzyme-linked immunosorbent assays showed that the expression of acute proinflammatory cytokines (interleukins 1alpha, 6, and 8, tumor necrosis factor alpha) peaked by 12-24 h postinjury. The levels of mRNA of certain growth factors (transforming growth factor beta1, vascular endothelial growth factor, insulin-like growth factor 2) but not others (platelet-derived growth factors A and B, keratinocyte growth factor, fibroblast growth factors 1 and 7, transforming growth factor beta3) increased by 12 h and peaked by 1-3 d after injury, returning to normal by day 6. Immunostaining for tumor necrosis factor alpha and transforming growth factor beta1 paralleled these findings by reverse transcription polymerase chain reaction. We conclude that human bilayered skin substitute, as a prototypic bilayered skin substitute, is a truly dynamic living tissue, capable of responding to physical injury in a staged and specific pattern of cell migration, reepithelialization, and cytokine expression.

The clinical features of facial and oral involvement in scleroderma are striking. We conducted a survey of patients with systemic sclerosis (scleroderma). The purpose of our study was to ascertain what was most bothersome aesthetically to scleroderma patients. We also looked at the differences between age groups and genders. The survey was mailed to 1,000 individuals who subscribe to a national lay group organization. We received 303 completed surveys indicating the patient's age, gender, age at onset of disease, and a checklist of 14 physical variables involving the central face and non-face. The respondents were asked to rate their level of concern [on a scale of great (1) -moderate (2) -little (3) -none (4)] in regards to 14 different physical variables. The respondents consisted of 92% females and 8% males. The mean age was 59 years +/- 13 (SD), and the median age was 60. The mean and median age at diagnosis was 45 years +/- 15 (SD). The percentage of respondents expressing concern for specific features was the following: for thin lips (73%), mouth furrows (80%), loss of facial lines (68%), and a smaller, tighter mouth (77%). There was less concern over the non-face features. The percentage of respondents expressing no concern was the following: for absence of sweating (57%), skin darkening (50%), nail dystrophy (57%), and skin atrophy (63%). There was a highly statistically significant difference (p<0.0001) between those respondents concerned with central face features vs. non-face features. With advancing age and longer disease duration, there was increased concern over the aforementioned central face features (p<0.0001). The vast majority of patients with systemic sclerosis have great concerns over changing facial features, and this worsens with age.