Human skin transcriptome during superficial cutaneous wound healing.

Healing of the epidermis is a crucial process for maintaining the skin's defense integrity and its resistance to environmental threats. Compromised wound healing renders the individual readily vulnerable to infections and loss of body homeostasis. To clarify the human response of reepithelialization, we biopsied split-thickness skin graft donor site wounds immediately before and after harvesting, as well as during the healing process 3 and 7 days thereafter. In all, 25 biopsies from eight patients qualified for the study. All samples were analyzed by genome-wide microarrays. Here, we identified the genes associated with normal skin reepithelialization over time and organized them by similarities according to their induction or suppression patterns during wound healing. Our results provide the first elaborate insight into the transcriptome during normal human epidermal wound healing. The data not only reveal novel genes associated with epidermal wound healing but also provide a fundamental basis for the translational interpretation of data acquired from experimental models.

Gene expression profiling of negative-pressure-treated skin graft donor site wounds.

Negative-pressure wound therapy (NPWT) is widely used to improve skin wound healing. Although NPWT has been studied as a treatment for wound closure and healing, the molecular mechanisms explaining its therapeutic effects remain unclear. To investigate the effect of NPWT on gene expression, and to discover the genes most dominantly responding to this treatment during skin wound healing, we applied negative pressure on split-thickness skin graft donor sites from the first postoperative day (POD) to the seventh POD. Biopsies were collected from 4 NPWT-treated and 2 control patients. Two biopsy samples were taken from each patient: one from intact skin before graft harvesting, and one on the seventh POD from the donor site wound. Genome-wide microarrays were performed on all samples. Gene expression changes on the seventh POD were compared between NPWT and control patients, and were analyzed for statistical significance. In addition, we analyzed wound exudates for volume, and for concentrations of leukocytes, erythrocytes, and haemoglobin. NPWT induced major changes in gene expression during healing. These changes ranged from 10-fold induction to 27-fold suppression. The genes most induced were associated with cell proliferation and inflammation, and the most down-regulated genes were linked to epidermal differentiation. Our results provide the first insight into the molecular mechanisms behind NPWT, and suggest that NPWT enhances specific inflammatory gene expression at the acute phase associated with epithelial migration and wound healing. However, its continued use may inhibit epithelial differentiation.