Archives of Dermatological Research

, Volume 300, Issue 1, pp 47–52

Photoaging-associated changes in epidermal proliferative cell fractions in vivo

  • Oh Sang Kwon
  • Hyeon Gyeong Yoo
  • Ji Hyun Han
  • Se Rah Lee
  • Jin Ho Chung
  • Hee Chul Eun
Short Communication

DOI: 10.1007/s00403-007-0812-3

Cite this article as:
Kwon, O.S., Yoo, H.G., Han, J.H. et al. Arch Dermatol Res (2008) 300: 47. doi:10.1007/s00403-007-0812-3

Abstract

The epidermis is a dynamic epithelium with constant renewal throughout life. Epidermal homeostasis depends on two types of proliferative cells, keratinocyte stem cells (KSCs), and transit amplifying (TA) cells. In the case of chronologic aging, levels of KSCs tend to decrease and change functionally. However, little is known about the effect of photoaging on epidermal proliferative subtype populations. The aim of this study was to validate involucrin/β1-integrin ratio as a molecular marker of epidermal photoaging, and to investigate the effects of photoaging caused by chronic UV exposure on the proliferative subtype populations. A total of 15 male volunteers (age range 20–24 and 77–85 years, Fitzpatrick skin phototype III–IV) provided sun-exposed and sun-protected skin samples for real-time RT-PCR, Western blot analysis and immunostaining. Fractional changes in proliferative subtype populations in photoaged and chronologically aged skins were analyzed by flow cytometry. The expression of β1-integrin was found to be significantly reduced in photoaged skin and ratios of the expressions of involucrin to β1-integrin were increased 2.6-fold only in elderly subjects. Interestingly, immunostaining of the sun-exposed skins of elderly subjects showed aberrant β1-integrin expression over the basal layer and greater numbers of Ki-67-positive cells than in sun-protected buttock skin. Flow cytometric analysis revealed that the proportion of KSCs to TA cells was reversed in sun-exposed and sun-protected skins of elderly subjects. Our results suggest that KSC numbers may be lower in photoaged skin than in chronologically aged skin and could be applied to hyperplastic pattern of photoaging. These findings suggest that the epidermis of photoaged skin is impaired in terms of its proliferative potential by attempting to repair chronic UV exposure and that photoaging may be associated with alteration in the two proliferative cell fractions.

Keywords

PhotoagingUltravioletKeratinocyte stem cellsInvolucrinβ1-integrin

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Oh Sang Kwon
    • 1
  • Hyeon Gyeong Yoo
    • 1
  • Ji Hyun Han
    • 1
  • Se Rah Lee
    • 1
  • Jin Ho Chung
    • 1
  • Hee Chul Eun
    • 1
  1. 1.Department of Dermatology, Seoul National University College of Medicine, Laboratory of Cutaneous Aging and Hair Research, Clinical Research Institute, Seoul National University Hospital, Institute of Dermatological ScienceSeoul National UniversitySeoulSouth Korea