Photoaging could be induced by accumulated DNA damage on skin cells. Photoaged skin has such characteristics as a nodular leathery surface with fine and coarse wrinkles, blotches and yellowing, dryness, teleangiectasia, and skin cancer formation. For this condition, chemical peeling, iontophoresis, laser and phototherapy are used with some improvement, especially in wrinkles and pigmentary uniformity.

The actual mechanisms of these treatments on photoaging continue to be actively studied. Glycolic acid may act on skin cells via keratinocytes and activate the cytokine network, which results in the remodeling of tissue construct and elimination of pigment. Heat generated by non-ablative laser or phototherapy might induce heat shock proteins which induce new collagen formation, and eliminate oxidized abnormal materials. This type of research is expected to disclose the cellular and molecular mechanisms of photoaging, and to lead to the establishment of further effective photoaging treatment.

Keywords: photoaging, cosmetic dermatology, chemical peeling, glycolic acid, skin rejuvenation, non-ablative laser, Intense pulsed light (IPL), heat shock protein (hsp), matrix metalloproteinase (MMP), thermal stimulation, advanced glycation end products (AGE), oxidative stress

Source: International Journal of Cosmetic Science, Volume 31, Number 1, February 2009 , pp. 75-75(1)