Cell kinetics and DNA content (ploidy) of human skin under expansion.

One question which still remains unanswered concerning expansion of human skin is whether expansion simply stretches the skin or whether it induces a real neo-production of epithelium. To evaluate the proliferative activity of the human skin before and after expansion, we performed an autoradiographic study and a densitometric analysis on sections of skin biopsy from 11 patients. The results of the cellular kinetic study showed that expansion induces an increase in the epidermal proliferative activity. On the contrary, the densitometric analysis did not show a parallel increase of the proliferating cells after expansion. This discrepancy is discussed in terms of the modified morphology of the tissue. The proliferative activity of skin in the back region increases more than in that of the neck. Preliminary results have shown that the proliferative activity increases with time of expansion in days. The presence of a low percentage of cells with altered DNA content indicates, at least over the short term, the absence of dysplastic processes in expanded skins.