The impact of sunlight on skin aging.
Current Geriatrics Reports
Purpose of Review
In this review, we summarize and discuss the current literature on photoaging. We focus on the molecular effects of UV radiation, and the histological and clinical features of chronically sun-exposed skin.
The expression of numerous proteins is altered in habitually sun-exposed skin, including sirtuins and hedgehog signaling proteins. Pharmacological manipulation of the levels of these proteins can potentially downregulate the photoaging process.
Mitochondrial and nuclear DNA damage, reactive oxygen species (ROS) production, and altered gene expression patterns are critical components of both photoaging and chronological aging. Chronic UVA and UVB exposure result in the photoaged phenotype through distinct molecular mechanisms, with UVA being primarily ROS-mediated and UVB being DNA damage-mediated. Molecular effects result in an altered dermal and epidermal environment that manifests as the photoaged phenotype. Importantly, skin phototype and environmental influences impact individual responses to chronic UV radiation.