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Stem cell-derived peptide offers alternative to topical retinol

There’s scientific evidence that a topical facial regimen containing defensin peptides rejuvenates facial skin much like topical retinoic acid but without associated irritation and inflammation, according to San Antonio, Texas, dermatologist Vivian Bucay, M.D.

Dr. Bucay, clinical assistant professor, University of Texas Health Science Center, San Antonio, was among the researchers to conduct a double-blind, vehicle-controlled study, including histologic analysis, of the DefenAge (Progenitor Biologics, a division of MediCell Technologies) skincare regimen. Researchers looked at whether the defensins-containing regimen would improve the structure and function of aging facial skin.

Defensins’ skin healing and potential rejuvenating effects can be traced to a type of stem cell. Defensins, which are antimicrobial peptides, activate an LGR6-positive stem cell locus in the hair follicle. LGR6-positive stem cells generate new epidermal cells during acute post-trauma wound healing.

Aesthetic physicians might use peels, laser procedures and more to traumatize skin and activate these stem cells.

“The idea was can we use defensins in a topical to activate the stem cells without having to traumatize the skin — without having to do a peel or laser procedure. We showed, that’s exactly what happened,” says Dr. Bucay who is part owner of MediCell Technologies.

Researchers studied 44 females, ages 41 to 70 years, with skin types I through V. Subjects used either the active regimen, including a serum, cream and mask containing alpha-defensin 5 and beta-defensin 3, or identical looking vehicle-only products. The women applied the cream and serum to the face and neck twice daily for 12 weeks and could use the mask twice a week. Researchers evaluated results using histopathology and immunohistochemistry in seven of the women. For all subjects, researchers evaluated pore size, clinically, and evaluated superficial and deep wrinkles based on Griffiths scale and high-resolution photography. Researchers also analyzed 15 patients using 3-dimensional imaging and skin care scores for evenness, pores, oiliness, as well as high-resolution skin ultrasound to determine trans epidermal water loss, elasticity, color and hydration.

Comparing the active and placebo groups’ baseline evaluations to results at six and 12 weeks, the researchers found that the active group’s epidermal thickness increased significantly, without inflammation, irritation or dryness.

“Specifically, this regimen increases epidermal thickness, reduces appearance of pores, reduces wrinkles and reduces melanin,” they write in the study published April 2018 in the Journal of Drugs in Dermatology. “This data is consistent with the hypothesis that a defensin-containing skincare regimen activates the body's own dormant stem cells to generate healthy new epidermal cells.”

Stem Cell Straight Talk

Claims that skincare products contain skin rejuvenating stem cells are misleading, according to Dr. Bucay.

“You can’t put a stem cell on the skin and expect it to do something. It’s not going to be alive,” she says.

Furthermore, it’s often a mystery if putting growth factors on the skin does anything at all to improve skin function or structure, she says.

“We hypothesize about the signaling cascade with growth factors. We know growth factors don’t penetrate the skin — they’re too big. So, even if they’re turning something on, they’re going to send signals to all kinds of stem cells, including stem cells that already have damage in them. It could also be a completely different set of stem cells that the growth factors are targeting,” Dr. Bucay says.

Defensins are peptides, not growth factors, which are small enough to easily penetrate into the pores, she says.

A Retinol Alternative, Adjunct

Doctors typically recommend gold standard retinol or retinoic acid to reduce typical signs of aging. But not all patients are good candidates for these topicals, according to Dr. Bucay.

Dr. Bucay says that ideal candidates for the DefenAge regimen include women who are or are thinking about getting pregnant because the topicals are not contraindicated in those patients. She also uses it for patients with sensitive or dry skin, who can’t tolerate retinoids.

“For patients who live in sunny areas, this is a good option because it’s not photosensitizing,” she says.

Dr. Bucay says she uses only the serum for patients with oily skin. And for acne patients already on retinoids, Dr. Bucay might combine DefenAge with topical retinoids to further improve skin appearance and function.

“The results we found in the study are comparable to what we find with retinoic acid,” she says.