TERMINAL DIFFERENTIATION OF FACIAL EPIDERMIS OF THE AGED - IMMUNOHISTOCHEMICAL STUDIES

In old age, the epidermis tends to become dry and flaky, especially on the lower legs. However, this does not occur on the face, although lo ng-term ultraviolet light irradiation has important effects on the dif ferentiation of facial keratinocytes. Therefore, the differentiation o f the epidermal cells of the facial skin in the young and the aged was immunohistochemically examined using antibodies against four differen tiation products: filaggrin, involucrin, cystatin A (CTA) and carbonic anhydrase-like protein. The results showed that there was no differen ce in the amounts of the above three proteins in facial skin between t he young and the aged with the exception of CTA. The amount of CTA was much greater in the facial skin of the aged. However, there was a str iking decrease of filaggrin content in the skin of the lower leg in th e aged. One of the reasons why no scaly skin is found on the face in t he aged may be the fact that especially filaggrin does not decrease wi th aging.