1203 Increased horizontal cell division and suppressed cell differentiation of pigmented basal keratinocytes in senile lentigo

Senile lentigo (SL) is a common hyperpigmented disorder that typically develops in chronically sun-exposed skin. It already known the accumulation of melanosomes keratinocytes (KCs) caused by activated melanocytes and delayed turnover accompanied aberrant epidermal differentiation. Some histological analyses show hyperplasia composed pigmented KCs SL. However, these mechanisms SL have been poorly understood. With age, epidermis normal skin has reported to hypoplasia due increased ratio asymmetric cell division basal (Nature. 2019 568:344-350). In this study, we hypothesized impaired balance symmetry might be involved formation, investigated orientation axis differentiation state compared To observe KCs, frozen sections (n=4) (n=5) were stained with anti-survivin antibody, measured angle against basement membrane. addition, anti-keratin 14, keratin 10 collagen XVII antibodies evaluate skin, horizontal among 0-30 degrees multilayered on membrane 14 XVII. Furthermore, immunostaining Fitzpatrick photo type V showed XVII-positive KCs. Our results suggested symmetric prevented from differentiation, resulting formation undifferentiated Further study will provide fundamental basis understand pathogenesis develop cosmetics medicines.