Page 68 - Read Online

Burke. Plast Aesthet Res 2020;7:59 Plastic and
DOI: 10.20517/2347-9264.2020.154 Aesthetic Research

Review Open Access

Environmental aging of the skin: new insights

Karen E. Burke

Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY 10022, USA.

Correspondence to: Dr. Karen E. Burke, Department of Dermatology, Icahn School of Medicine at Mount Sinai, River Court
Building, 429 East 52nd Street, New York, NY 10022, USA. E-mail: kebmdphd@gmail.com

How to cite this article: Burke KE. Environmental aging of the skin: new insights. Plast Aesthet Res 2020;7:59.
http://dx.doi.org/10.20517/2347-9264.2020.154

Received: 26 Jul 2020 First Decision: 10 Aug 2020 Revised: 19 Aug 2020 Accepted: 22 Sep 2020 Published: 24 Oct 2020
Academic Editor: Salvador Gonzalez Copy Editor: Cai-Hong Wang Production Editor: Jing Yu

Abstract
The appearance of aging is determined primarily by extrinsic factors through exposure to environmental sunlight
and airborne pollution. That solar ultraviolet B (λ = 290-320 nm) directly causes photoaging (with wrinkles,
dryness, and mottled pigmentation) and skin cancer has been recognized for decades; the contribution by
ultraviolet A (λ = 320-400 nm) was only more recently understood. New research further implicates visible light
(λ = 400-700 nm) as well as the heat rays of infrared radiation (λ > 800 nm). Particularly in urban environments,
airborne pollutants such as ozone (O 3 ), polycyclic aromatic hydrocarbons, particulate matter (PM) in smog,
and tobacco smoke contribute to photoaging and skin cancer. Furthermore, exposure simultaneously to both
solar ultraviolet (UV) and these pollutants results in even greater synergistic damage. The volatile pollutants
generate reactive oxygen species which oxidize surface lipids leading to deeper damaging inflammatory reactions.
PM carries high concentrations of environmental organic compounds and trace metals. These pollutant-laden
particles deliver toxins to the skin transcutaneously through hair follicles and through the blood after respiratory
inhalation. The predominant natural mechanism of clearing these xenobiotic chemicals is through the ligand-
activated transcription factor the arylhydrocarbon receptor (AHR) found on all skin cells. AHR activity regulates
keratinocyte differentiation and proliferation, maintenance of epidermal barrier function, melanogenesis, and
immunity. With chronic activation by UV exposure and pollutants, AHR signaling contributes to both extrinsic
aging and carcinogenesis.

Keywords: Ultraviolet-induced aging, pollution, smoking, ozone, skin cancer, particulate matter, aryl hydrocarbon
receptor

© The Author(s) 2020. Open Access This article is licensed under a Creative Commons Attribution 4.0
International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
sharing, adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as long
as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license,
and indicate if changes were made.

www.parjournal.net