Affiliations: Tokiwa Pharmaceutical Campany Product Development,
Japan | Kaneka Corporation Functional Food Ingredients
Division, Japan | Doshisha University, Japan
Note: [] Address for correspondence: Masamitsu Ichihashi, Department of
Skin Aging and Photoaging Research Center, Doshisha University, TRI-301, 1-5-4
Minatojima Minami-machi, Chuo-ku, Kobe 650-0047, Japan. E-mail:
[email protected]
Abstract: Photodamaged skin exhibits wrinkles, pigmented spots, dryness and
tumors. Solar UV radiation induces cyclobutane pyrimidine dimers (CPD) and
further produces base oxidation by reactive oxygen species (ROS). ROS are
thought to be a major factor to initiate the up-regulation of matrix
metalloproteinases (MMPs) in keratinocytes and fibroblasts via activation of
receptor proteins on the cell membrane of keratinocytes and fibroblasts, and to
degrade fiber components in dermis, leading to wrinkle formation. Coenzyme Q_{10} (CoQ_{10}) was
reported to reduce ROS production and DNA damage triggered by UVA irradiation
in human keratinocytes in vitro. Further, CoQ10 was shown to reduce UVA-induced
MMPs in cultured human dermal fibroblasts. We speculated that UVB radiation-induced cytokine production in
keratinocytes may be inhibited by CoQ_{10}, resulting in the
reduction of MMPs in fibroblasts leading to wrinkle reduction. Our in
vitro studies showed that UVB-induced IL-6 production of normal human
keratinocyte (NHKC) decreased in the presence of CoQ_{10}.
Furthermore, MMP-1 production of fibroblasts cultured with the medium
containing CoQ_{10} collected from UVB-irradiated NHKC
significantly decreased during 24 h culture. In the clinical trial study, we
found that the use of 1% CoQ_{10} cream for five months reduced wrinkle
score grade observed by a dermatologist. Taken together, our results indicate
that CoQ_{10} may inhibit the production of IL-6 which
stimulate fibroblasts in dermis by paracrine manner to up-regulate MMPs
production, and contribute to protecting dermal fiber components from
degradation, leading to rejuvenation of wrinkled skin.
