A new study looks at how lasers affect molecular pathways to reduce signs of aging.
Forget the scalpel. For years, many dermatologists have turned to lasers to reduce signs of aging with minimal recovery time. While the procedure to help resurface skin and diminish fine lines works, researchers were not sure how lasers helped improve the skin until now.
In a new study, researchers say they have a better idea of how skin rejuvenates itself after laser treatments — something they hope could lead to improved therapies.
A team from Johns Hopkins University found laser treatments and retinoic acid, more widely known as Retin-A, have a common molecular pathway.
Retin-A is a derivative of vitamin A. It’s commercially produced and used to treat acne, wrinkles, and sunspots.
The team found that the molecular pathway they discovered allows skin cells to sense loose RNA molecules.
The team found the pathway also helped mice regenerate hair follicles — something that doesn’t happen in humans.
Dr. Luis Garza, an associate professor of dermatology at the Johns Hopkins University School of Medicine, said previous research found that loose pieces of RNA, known as self-noncoding double-stranded RNA (dsRNA), can trigger regeneration after a wound. Garza thought the dsRNA is released by damaged cells, and wanted to see how it happened with laser therapy, a common skin rejuvenation procedure used by dermatologists.
Treatments such as laser therapy, microneedling, and facial abrasion all involve temporarily damaging skin cells. Garza said the treatments are regularly used among dermatologists, but the medical community didn’t have a clear understanding of how or why they work.
“They’re actually working in the same molecular pathways, and nobody knew that until now,” he noted.
While many people buy Retin-A to apply topically, in this case, the lasers were helping to kickstart the production of Retin-A in the body.
“Lasers induce dsRNA release that then triggers local retinoic acid production that promotes rejuvenation and regeneration,” Garza told Healthline.
Garza said it’s the body’s attempt to heal itself that helps diminish the signs of aging.
“Retinoic acid works because it mimics what our body normally does for regeneration after a wound. Lasers work because they induce local retinoic acid production. DsRNA is the unknown link between the two,” he said.
Garza’s team collected biopsies from 17 participants being treated at the Johns Hopkins Hospital. The patients were undergoing conventional laser skin rejuvenation on their face and arms with a nonablative fractional laser. The lasers are known to diminish and erase sunspots and wrinkles. All patients were Caucasian women with an average age of 55. The researchers collected skin biopsies before the laser treatment and one week after the laser treatment.
When they looked at the expression levels of genes in each sample, they noted that genes involved in sensing dsRNA, as well as genes involved in producing the skin’s natural retinoic acid, were all expressed at higher levels after the laser treatment.
The researchers applied loose dsRNA to isolated human skin cells, which mimicked the effect of a laser treatment. They found that the amount of retinoic acid generated inside the cells increased by more than tenfold.
Garza’s team also analyzed mice as part of the study, as they can regenerate hair follicles after a wound. A protein called toll-like receptor 3 (TLR3) senses dsRNA in mice and humans.
When his group created mice to lack TLR3, the animals could no longer regenerate hair follicles after a wound. But, when the researchers gave the mice retinoic acid, they found that the mice could regenerate the follicles again. Garza said the results indicate a pathway involving TLR3 that senses dsRNA and synthesizes retinoic acid.
“Double-stranded RNA may be able to improve the appearance of burn scars,” he said.
Dr. Kristen Kelly, a professor in the department of dermatology and surgery at the University of California, Irvine, said other studies have shed light into how retinoic acid and lasers work. Garza’s findings add more insight into the process that makes the treatments work. She wasn’t affiliated with the research.
“There may be some similarities in the pathways of repair stimulated by retinoic acid and nonablative lasers,” Kelly said.
There are a variety of different lasers on the market, Kelly said. Nonablative fractional lasers, as used in the study, heat the underlying skin tissue without damaging the surface of the skin. Ablative lasers remove the top layer of skin.
Both can be effective, but, “Ablative fractional resurfacing gives more impressive results,” Kelly said. The drawback is that ablative laser treatments come with more downtime and side effects. Nonablative lasers are used for those with milder damage or when a gentler treatment is desired.
Peels, radiofrequency devices, and ultrasound technologies are laser alternatives that can also rejuvenate the skin. Not all resurface the skin the way an ablative laser does.
Joining retinoic acid and laser treatments in new ways could improve skin appearance while reducing damage, and regenerate hair follicles, Garza said.
Dermatologists already combine lasers and retinoic acid. After a laser treatment, a person may take time to heal and then apply retinoic acid topically to maintain some of the results, Kelly said.
“Retinoic acid enhances the effects of laser treatment,” Garza noted. “Some dermatologists do use them together, and our data suggest they should be used more often together.”
Garza explained that his university holds a patent that would allow the researchers to formulate dsRNA and retinoic acid to a more potent drug to enhance regeneration and rejuvenation. It could treat photoaging or help with wound healing, he said.
Theoretically, he hopes researchers can create a prescription dsRNA that could be applied to burn scars, for example, to enhance skin cell regeneration.
“This could eventually replace the need to do painful treatments like laser therapy,” he said.
The development could lead to hair regeneration therapies, as dsRNA or retinoic acid may promote hair follicle regenesis in humans. Garza said it hasn’t been seen yet and would need to be further tested.
Garza’s team will do more testing to see which dsRNA formulations might be best to promote regeneration and rejuvenation for use in clinics, he said.