There is a shift in skin aging by decades, depending on ethnicity, according to results of a scientific evaluation underwritten by Proctor & Gamble Co.
“The studies compare Caucasian, African Americans, Latinos and Asian patients to each other at various decade intervals,” says Maritza Perez, M.D., a clinical professor of dermatology at Mount Sinai Icahn School of Medicine in New York City.
Patients were selected at different decades of their lives: 20s, 40s and 60s. Each patient then mailed a saliva sample to 23andMe in Boston, a genomics and biotechnology company similar to Ancestery.com, to verify their ethnicity.
Patients had facial photographs taken to evaluate facial skin appearance based on assessment of youthfulness in pair-wise comparisons of subject facial images as compared to chronological age of the subjects. “These pictures from different decades were then analyzed to determine the evolution of the aging process in the different ethnicities” Dr. Perez says.
The evaluation showed, for example, in two patients who are 64 years old — one African American, the other Caucasian — “there is a shift of 10 years,” says Dr. Perez, who is a scientific advisor to Proctor & Gamble. “In other words, the African American patient looks 10 years younger than the 64-year-old Caucasian patient.”
Skin biopsy samples from photoexposed (face, outer forearm) and photoprotected (buttocks) body sites were obtained and analyzed for RNA extraction from full thickness biopsies and laser-capture microdissected skin samples. Extracted RNA was used to code for trancriptonics.
DNA from biopsies can ascertain if there are differences in transcriptions by translating for proteins at different decades of life, “for which you will find that some proteins are upregulated, while others are downregulated,” Dr. Perez says.
The transcription tendency of these proteins indicates that a 50-year-old Caucasian patient has equivalent transcription identification to a 60-year-old African American.
In addition, when isolating a marker for cellular senescence in African Americans and Caucasians, “in both groups, in the exposed areas of the arms and face, there is an increase in cellular senescence as the decades pass and is augmented by sun exposure,” says Dr. Perez, who spoke at the Skin of Color Seminar Series (SOCSS) in New York City in May. “However, this increase in cellular senescence and sun exposure has a much more adverse effect on Caucasians than African Americans.”
On the other hand, histology shows that Latinos and Caucasians have similar elastotic changes at age 60. “Surprisingly, though, this metric was not documented in the African American population,” Dr. Perez says.
The studies for the Proctor & Gamble project are being conducted by Alexandra Kimball, M.D., chief executive officer of Harvard Medical Faculty Physicians (HMFP) at Beth Israel Deaconess Medical Center in Boston.
By detecting an increase in cellular senescence, a sunblock might be recommended to a patient. “The study found that patients who cover themselves from the sun showed less increase in cellular senescence than those with risky behavior under the sun,” Dr. Perez says. “Thus, a combination of education and intervention is required.”
Dr. Perez believes that dermatologists should not treat solely on chronological age or skin color. “Still, you can interfere or intervene with the development of cellular senescence with retinoids, antioxidants and growth factors,” she says. “But you need a marker to document the cellular senescence.”
One of the main goals of the aging project is how to define products for different ethnic populations, depending on their needs.
“It is important to know that these populations were readily identified genetically because so many people are of mixed ethnicity,” Dr. Perez says. “Once we have all this information collected, I think that we as dermatologists will be able to interfere or intervene in each one of these populations in a different fashion; for example, starting sunblock in Caucasians very early in life to lessen the effects of sun damage.”
Despite Dr. Perez does not advocate that patients have a genetic workup so that they can have more targeted therapy.
“A genetic profile may never become standard of care, but it could become important in the management of patients,” Dr. Perez says. Â
Disclosure: Dr. Perez is a scientific advisor to Proctor & Gamble Co.