The research published in this month's Experimental Dermatology highlights the role of UVB radiation in photoaging and concludes that the belief that 'UVA is for Aging' is not the full story.
The scientists led by Daniel B Yarosh from New York-based skincare company AGI Dermatics investigated the relationship between UV radiation, DNA damage, the expression of MMP-1 and the degradation of collagen in the skin.
UVB is the main culprit "The common misconception that UVA is responsible for aging as it penetrates deeper and has a direct effect on collagen is not the case" , Yarosh told CosmeticsDesign.com.
"This research highlights the importance of UVB in skin ageing.
The sunlight triggers the release of enzymes in the top layer of the skin which then travel to the lower layers and do the damage," he said.
According to Yarosh, the recent focus on UVA protection has led to improved protection in suncare products however we should not forget the significant role UVB plays in the affair.
"For competitive reasons manufacturers started concentrating on UVA protection as most products had a similar level of UVB protection" he explained, emphasizing however that UVB is the main culprit.
UVB radiation induces damage in the epidermal DNA causing changes to its structure and initiating the release of MMP-1, a major factor in the degradation of collagen.
In addition, UVB can induce MMP-1 expression indirectly through the production of other cell signalling factors that can then act on non radiated fibroblasts and increase MMP-1 levels, according to the study.
Topical application reduces damage
The team encapsulated three enzymes that help repair DNA damage, T4 endonuclease V, UV endonuclease and photolyase and noted that topical application led to reduced levels of MMP-1 in the skin.
Sixteen individuals aged between 18 and 65 years were treated with a liposomal photolyase lotion followed by exposure to UVB radiation.
Skin biopsies were then taken to determine the MMP-1 gene and protein expression.
AGI Dermatics currently offers these ingredients for use in anti-aging products as well as producing a line of finished products available through the physician channels.