| Cultured skin substitutes (CSS) were used as a wound healing model to evaluate the effects of vernix caseosa (VC) in vitro. The barrier development in these substitutes was first evaluated to get a detailed understanding of the time course of barrier maturation in vitro and post grafting ex vivo. Optimum barrier function in vitro was observed on day 14; however, the optimum values were far from those obtained with native human skin controls. Additional CSS were grafted on athymic mice on day 14, and skin was harvested 2 weeks and 6 weeks post grafting. Grafting brought about a substantial decrease in all measurements by 2 weeks and almost complete normalization of barrier function after 6 weeks.; In order to grow these tissues in a format more suitable for in vitro testing, a modified method was developed. Post inoculation and lifting to air liquid interface (day 5 in vitro) the tissue was transferred to and maintained on Franz diffusion cells for the rest of the period of incubation. A significant improvement in barrier function was observed for tissue grown by this method.; The effect of VC on barrier development was tested on CSS grown by this modified method. CSS with and without VC treatment were evaluated for changes in viability, morphology, barrier function and epidermal metabolism from day 7 to 21 of incubation in vitro. Lactate production was significantly higher in VC-treated tissue in the early phases of CSS development, when the barrier function was impaired. However, no significant improvement in barrier function was observed with VC treatment.; The effect of VC in vivo was evaluated in a barrier repair clinical trial. Stratum corneum damage was created on 6 volar forearm sites by tape stripping until transepidermal water loss was 32--40 g/m2/hr, comparable to those of preterm infants of 26--27 wks gestation. Sites were treated with no occlusion, VC, complete occlusion, AquaphorRTM, oil-in-water emulsion and a semipermeable film. Transepidermal water loss, moisture accumulation rate, hydration and pH measurements were made at baseline, day 3 and 5. VC showed only significant improvement over complete occlusion. |
