- 作者：Takaaki Yamada ; Seiji Hasegawa ; Yu Inoue ; Yasushi Date ; Masaru Arima ; Akiko Yagami ; Yohei Iwata ; Masamichi Abe ; Masayuki Takahashi ; Naoki Yamamoto ; Hiroshi Mizutani ; Satoru Nakata ; Kayoko Matsunaga ; Hirohiko Akamatsu
- 关键词：Solar lentigines ; Melanocyte ; Melanoblast ; Melanocyte stem cell ; Differentiation
- 刊名：Journal of Dermatological Science
- 出版年：March, 2014
- 年：2014
- 卷：73
- 期：3
- 页码：251-257
- 全文大小：1868 K
Background
Solar lentigines (SLs) are characterized by hyperpigmented macules, commonly seen on sun-exposed areas of the skin. Although it has been reported that an increase in the number of melanocytes and epidermal melanin content was observed in the lesions, the following questions remain to be answered: (1) Is acceleration of melanogenesis in the epidermis caused by an increased number of melanocytes or the high melanogenic potential of each melanocyte? (2) Why does the number of melanocytes increase?Objective
To elucidate the pathogenic mechanism of SLs by investigating the number, melanogenic potential and proliferation status of the melanocyte lineage in healthy skin and SL lesions.
Methods
Immunostaining for melanocyte lineage markers (tyrosinase, MART-1, MITF, and Frizzled-4) and a proliferation marker, Ki67, was performed on skin sections, and the obtained images were analyzed by image analysis software.
Results
The expression level of tyrosinase to MART-1 of each melanocyte was significantly higher in SL lesions than healthy skin. The numbers of melanocytes in the epidermis, melanoblasts in the hair follicular infundibulum and melanocyte stem cells in the bulge region were increased in SL; however, no significant difference was observed in the Ki67-positive rate of these cells.
Conclusion
The melanogenic potential of each melanocyte was elevated in SL lesions. It was suggested that the increased number of melanocytes in the SL epidermis might be attributed to the abnormal increase of melanocyte stem cells in the bulge.