CURRENT CONCEPTS IN PEDIATRIC BURN CARE - THE BIOLOGY OF CULTURED EPITHELIAL AUTOGRAFTS - AN 8-YEAR STUDY IN PEDIATRIC BURN PATIENTS

An 8-year histopathological study of skin regeneration and wound healing in 22 pediatric patients treated with cultured epithelial autografts (CEA) grafted to full-thickness bum wounds excised to muscle fascia is reported. Biopsies of CEA have been analyzed by light microscopic, immunohistochemical, morphometric, electron microscopic and ultrastructural immunolabelling techniques and compared to controls of meshed split-thickness autograft (MSTA) interstices at comparable times postgrafting. At transplantation, CEA are undifferentiated and lack both granular and cornified cell layers. By 6 days postgrafting, CEA differentiate all normal epidermal strata but lack rete ridges. De novo formation of a confluent basal lamina and mature hemidesmosomes is complete by about 3 weeks. Anchoring fibrils appear sparse and immature (as in MSTA controls) compared to normal skin until about 6-12 months. CEA develop rete ridges and a neodermis with normal stromal and vascular organization at about 6-12 months, whereas MSTA interstice controls do not. At 4-5 years, elastin expression is also observed in the CEA neodermis, completing the dermal regeneration process. Normal epidermal differentiation is maintained long-term. These long-term results indicate that CEA regenerate a stable normal epidermis and are capable of inducing dermal regeneration from wound bed connective tissue.