Mikio Koide

Histological evaluation of skin reconstruction using artificial dermis

An artificial dermis, composed of a collagen matrix, was applied to a full-thickness skin defect prepared on the back of rats. Two weeks later, a thin split-thickness skin autograft was overlaid on the matrix at each recipient site. The dermal layer at the recipient sites was 1.02 mm thick with prior application of artificial dermis, as compared with the 0.46 mm thickness observed without such pretreatment. Histologically, the split-thickness skin graft normally lies with no gap on the artificial dermis, which looks like natural dermis. Six days after grafting, the epithelial basal cells in the grafts showed an active uptake of bromodeoxyuridine (a thymidine analogue), indicating high activity of cell proliferation. About 50 and 20% respectively of the artificial dermis remained at each recipient site at 12 and 20 weeks after its application (after the skin defect). This finding indicates that bovine collagen, which is a constituent of the artificial dermis, is gradually replaced by the host tissue.

Evaluation of an artificial dermis full-thickness skin defect model in the rat

An artificial dermis product was applied to full-thickness skin defects in rats and cell infiltration into the collagen matrix was investigated. Host fibroblasts and capillaries infiltrated as far as the upper end of the collagen matrix by day 14 after application. Determination of glycosaminoglycan levels in the matrix showed that hyaluronic acid was generated in a similar amount to that seen in the intact skin by day 14. An autologous thin split-thickness skin graft was placed onto the artificial dermis simultaneously or several days after its application to the defect. The take rate was 100% when a split-thickness skin graft was performed on day 14 after application of the artificial dermis. At 6 weeks after the skin defect was created, the wound area was 80% of the original area and the dermis at the grafted site was as thick as that of normal skin. These results suggested that the artificial dermis provides a good matrix for thin split-thickness skin graft and is useful for the reconstruction of full-thickness skin defects. This method is considered to be an alternative to the conventional procedure using thick skin grafts or skin flaps.

The Effect of a Collagenous Implant on Deep Dermo‐Periosteal Defects in the Rabbit

In plastic surgey, extensive wounds with exposed bone and loss of the periosteum (i.e., deep dermo‐periosteal defects) are difficult to treat, even with split‐thickness skin grafts, because such grafts rarely survive. Even when these grafts do survive, functional impairment often occurs subsequently. The application of a collagen sponge (Terudermis®, Terumo, Tokyo) to such wounds has previously been reported to accelerate granulation tissue formation, resulting in would healing and graft survival. However, this previous report only presented data relating to gross morphological appearance