SAN DIEGO – Using the according to Molly Wanner, MD, MBA.
As a case in point, Dr. Wanner discussed the results of a trial of 48 people over aged 60 years with actinic damage, who received ablative fractional laser treatment on one arm and no treatment on the other arm, which served as the control. At 24 months, only two nonmelanoma skin cancers (NMSCs) developed on the treated arms, compared with 26 on the treated arms.
“What I find interesting is that the treated arm did not develop basal cell carcinoma, only squamous cell carcinoma,” she said at the annual meeting of the American Society for Laser Medicine and Surgery. “It appears that this is working through more than just treatment of the AK precursor lesions, for which fractional lasers are cleared for use. It appears to impact both types of NMSCs.”
The ablative fractional laser and other wounding therapies can modulate a response to UV light – a process that naturally diminishes with age, according to Dr. Wanner, a dermatologist at Massachusetts General Hospital’s Dermatology Laser and Cosmetic Center in Boston. “This ability to repair DNA is actually modulated by insulin-like growth factor 1,” she said. “IGF-1 is produced by papillary dermal fibroblasts and communicates with keratinocytes. If keratinocytes are exposed to UV light and there is no IGF-1 around, you get a mutated cell, and that keeps spreading, and you could potentially get a skin cancer.”
On the other hand, she continued, if IGF-1 is injected around the keratinocytes, they are able to respond. “Keratinocytes, which are the most superficial layer of the skin, are really active,” noted Dr. Wanner, who is also an assistant professor of dermatology at Harvard Medical School, Boston. “They’re dividing and replicating, whereas fibroblasts are more non-proliferative and more long-lived. They stick around for a long time. I think of them as the adults in the room, giving these new keratinocytes direction.”
In a review of wounding therapies for the prevention of photocarcinogenesis, she and her coauthors noted that IGF-1 increases nucleotide excision repair of damaged DNA, promotes checkpoint signaling and suppression of DNA synthesis, favors specialized polymerases that are better able to repair DNA damage, and enhances p53-dependent transcriptional responses to DNA damage.
“Older fibroblasts produce less IGF-1 and lead to a situation where keratinocytes can grow unchecked,” she said. “We can use fractional laser to help with this. Fractional laser increases fibroblast production and decreases senescent fibroblasts.”
In a 2017 review on the impact of age and IGF-1 on DNA damage responses in UV-irradiated skin, the authors noted the high levels of IGF-1 in the skin of younger individuals and lower levels in the skin of their older counterparts.
“But once older skin has been treated with either dermabrasion or fractional laser, the levels of IGF-1 are restored to that of a young adult,” Dr. Wanner said. “The restoration of IGF-1 then restores that level of appropriate response to UV light. So, what’s interesting is that fractional lasers treat more than a fraction [of skin]. Fractional lasers were developed to have an easier way to improve wound healing by leaving the skin intact around these columns [of treated skin]. It turns out that treatment of these columns of skin does not just impact the cells in that area. There is a true global effect that’s allowing us to almost normalize skin.”
Dr. Wanner now thinks of fractional lasers as stimulating a laser-cell biology interaction, not just a laser-tissue interaction. “It’s incredible that we can use these photons to not only impact the tissue itself but how the cells actually respond,” she said. “What’s going to be interesting for us in the next few years is to look at how lasers impact our cellular biology. How can we harness it to help our patients?”
She and her colleagues are conducting a trial of different wounding modalities to assess their impact on IGF-1. “Does depth matter? Does density matter? Does the wavelength matter?” she asked. “The bottom line is, it turns out that when the skin looks healthier, it is healthier. Cosmetic treatments can impact medical outcomes.”
Dr. Wanner disclosed that she is a consultant and advisor to Nu Skin. She has also received research funding and equipment from Solta.