Use of keratinocytes in combination with a dermal replacement to treat skin loss - Biomaterials for Treating Skin Loss - page 208

13.1 Long-term studies in guinea pigs (1 year) show that tissue
reorganizes and differs from scar (Butler et al. , 1999).
seeding or expansion in culture (Butler et al ., 1999). While uncultured keratinocytes
can be harvested, disaggregated, seeded and grafted within 4 hours (Butler et al .,
1999), cultured autologous keartinocytes cannot be made available at short notice
(Butler et al ., 1999).
In elective cases, autologous keratinocytes can be expanded in culture to have a
more extensive population on the day of grafting. Shorter culture time periods can
be used to allow earlier seeded graft production; however, this trade-off signifi-
cantly reduces the cell expansion capabilities (Butler et al ., 1999). Although
cultured keratinocytes require more time than uncultured ones, they allow selec-
tion of proliferating cells and provide the potential to restore bylayer tissues with
smaller donor sites (Butler et al ., 1999). In addition, cultured cell-seeded matrices
induced faster (96% on day 14, versus 50% achieved by uncultured matrices) and
thicker re-epithelialization when compared to uncultured cell-seeded matrices
(Butler et al ., 1999).
To simplify the surgical manipulation, sheets of cultured, autologous
keratinocytes can be also grafted to the undersite of the dermal matrix (Jones et al .,
2003), showing the natural tendency to migrate upwards and achieve epidermal
confluence, but less efficiently than when centrifuged directly into the scaffolds
(Jones et al ., 2003; Orgill et al ., 1998; Orgill et al ., 1999).
More recently new methodologies have been proposed to deliver keratinocytes
in combination with dermal scaffolds. The introduction of an autologous cell
suspension (cell spray) enables the keratinocytes to be delivered to the wound via