P2.17 Loss of EPIDERMAL Stem Cells BY Cellular Senescence

Dong-Seok Kim¹, Sang-Woong Youn², Hyun-Ju Cho², Hye-Ryung Choi², Sang-Eun Jeon², Ho-Joon Yoon², Kyoung-Chan Park²

¹ Research Division for Human Life Sciences, ² Department of Dermatology, Seoul National University College of Medicine, Seoul, South Korea

Objectives: The aim of this study was to investigate the effects of cellular senescence caused by chronological aging or by repeated subculture. The effects of cellular senescence were investigated using monolayer cultures of keratinocytes and reconstructed epidermis.

Methods: We prepared keratinocytes from donors of different ages and by repeated subculture. Flow cytometric analysis was performed using α₆ integrin antibody and CD71 antibody and candidate keratinocyte stem cell populations were separated according to reactivities to these two different antibodies. Living skin equivalents (LSEs) were reconstructed using keratinocytes from children, adults and elderly donors.

Results: Flow cytometric analysis showed a decrease in the stem cell proportion in an age and culture passage-dependent manner. LSE experiments showed that a reconstructed epidermis using child’s keratinocytes was well formed compared to epidermis reconstructed using an elderly donor’s keratinocytes. Different expression of proliferation markers was also observed according to donor age.

Conclusions: Our results show that cellular senescence by chronological aging or repeated sub-culture induced the loss of stem cell proportion in epidermis. This seems to be the reason why it is difficult to culture keratinocytes from the elderly or by repeatedly culturing keratinocytes.