Wound Healing Processes occuring in Hyposkin® Model
HypoSkin® is an ex vivo human skin model with epidermis, dermis, and hypodermis. The skin explant is embedded in a proprietary gel-like matrix with the epidermal surface left in direct contact with the air.
To generate a wound, a defect of a controlled diameter is performed to remove all the epidermis and upper part of the dermis. A silicon ring is adhered on the skin surface to prevent lateral bacteria leakage. The system is mounted into cell culture inserts and maintained in standard cell culture conditions.
A human ex vivo model suitable for bacterial infection
At day 0, the edge of the wound was a clear cut of the epidermis. From day 2, an epithelial tongue appeared and migrated until day 7. A crust was also visible at day 7. Cells in the migrating epithelial tongue were proliferating (Ki-67 positive staining) and expressing K17 which is a specific marker of keratinocytes migrating over the wound bed.
Wounded HypoSkin® recapitulates some aspects of wound healing
Wound infection with Staphylococcus aureus
Number of bacteria colony forming units (CFU) in skin infected for 4 days by different concentrations of S. aureus is showed on the graph. No bacteria were detected on uninfected skin (control). The detected amount of bacteria in infected skins was ≈1×10^8 CFU/g of skin.
Skin containing S. Aureus bacteria
Staphylococus Aureus Colonization
Biofilm developement on the wound (A-B)
Hematoxylin and eosin staining shows the structure of the wound (dermis in pink) and bacteria (dark purple). A S. aureus biofilm developed over 4 days of infection in the wound.
S. Aureus specific biofilm (C-D)
S. Aureus was detected on tissue sections by using a specific antibody. High level of green fluorescence indicates the presence of S.aureus within the wound.
Bacterial colonization of skin tissue (E-F)
Scanning electron microscopy analysis shows presence of bacteria among collagen fibers.
Histological Observations of Infected Wounds
