Abstract
Background
While skin color is the most notable difference among ethnic skins the current knowledge
on skin physiological and aging properties are based mainly on Caucasian skin studies.
Objective
To evaluate histological differences in elastin fiber network and differential responsiveness
to TGF-β in skin of Caucasians and African Americans.
Methods
These studies were undertaken using human skin biopsies, primary dermal fibroblasts,
Western blot analyses, immunofluorescence microscopy, cDNA array and quantitative
real-time PCR.
Results
In Caucasian subjects, tropoelastin expression and elastin fibers in photoprotected
skin was substantially less than in age-matched African American skin. Expression
of tropoelastin in photoexposed skin of African American was similar to their photoprotected
skin, suggesting that photoexposure did not affect elastin fibers in African American
skin to the same extent as Caucasian skin. An elevated level of TGF-β1 present in
media from dermal fibroblasts derived from African American skins correlated well
with the higher levels of TGF-β mRNA in African American skins analyzed by cDNA array.
Treatment with TGF-β1 resulted in a considerably higher induction of elastin mRNA
in dermal fibroblasts from African Americans than from Caucasian fibroblasts, indicative
of enhanced TGF-β signaling in African American skins. Furthermore, UVA exposure decreased
levels of elastin mRNA in Caucasian fibroblasts compared to African Americans fibroblasts.
Conclusion
These results suggest that there are ethnic differences in the elastin fiber network
and in TGF-β signaling in African American and Caucasian skin, and that African American
have less UV dependent loss of elastin than Caucasian which may contribute to the
different perceived aging phenotypes.
Keywords
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Article info
Publication history
Published online: April 15, 2013
Accepted:
March 7,
2013
Received in revised form:
February 1,
2013
Received:
August 28,
2012
Identification
Copyright
© 2013 Japanese Society for Investigative Dermatology. Published by Elsevier Inc. All rights reserved.
