Why some people seem to keep more youthful-looking skin even as they age is a mystery often attributed to winning the genetic lottery. To investigate this process, researchers from the Beth Israel Deaconess Medical Center of Harvard University have analyzed patterns of gene expression that underlie skin aging.
According to the study, published in Journal of the American Academy of Dermatology, the research team collected skin biopsy samples from 158 Caucasian women ranging from 20 to 74 years of age. These samples were obtained from parts commonly exposed to sunlight (face and arm), as well as sections less exposed (buttocks). The physical appearance of facial skin were measured through digital images.
Histologic and transcriptomics profiling on the samples revealed expression of genes related to oxidative stress, energy metabolism, senescence, and epidermal barrier. These changes were accelerated in the 60s and 70s. The comparison of sun-exposed and sun-protected skin samples also revealed that certain changes in gene expression are likely due to effects of photoaging.
"It's not just the genes you are born with, but which ones turn on and off over time," said senior author Alexa B. Kimball. "We found a wide range of processes in the skin affected by aging, and we discovered specific gene expression patterns in women who appear younger than their chronologic age."
Based on appearance of youthfulness, women who were younger-looking actually exhibited gene expression patterns more similar to those of younger women. These women had increased activity in genes associated with basic biologic processes, including DNA repair, cell replication, response to oxidative stress, and protein metabolism. Older women with exceptionally youthful-appearing facial skin were also found to upregulate genes related to mitochondrial structure and metabolism, overall epidermal structure, barrier function, and dermal matrix production. “It seems that their skin looked younger because it behaved younger," Kimball noted.
A better understanding of the gene expression driving youthful skin appearance may lead to new strategies in slowing the aging process. The team’s findings also confirm that ultraviolent (UV) exposure accelerates skin aging. "Improving our understanding of which choices and factors led to this specific profile is likely to be of great interest across the ages," says Kimball.