LEDs shine bright as source for novel photorejuvenation technique

Light-emitting diodes (LEDs) are the ideal source for photomodulation, a recently developed photorejuvenation method using non-thermal stimulation of skin cells with low energy and narrowband lights, according to a recently published review paper authored by a team of German researchers.

Dr. Helbig

This and other findings are in a review paper published in the June 2010 issue of International Journal of Cosmetic Science. The paper summarizes what is known today about intrinsic and extrinsic skin aging and existing skin rejuvenation methods, with a special focus on laser and light methods.

SPOTLIGHT ON LED LED photobiomodulation is the newest category of nonthermal light therapies, according to Dr. Helbig and her researchers.

"LEDs ... have been used for skin rejuvenation alone and in combination with other thermal or ablative skin rejuvenation treatments. LEDs have been demonstrated as having anti-inflammatory potential," Dr. Helbig says. "LED irradiations have been shown to increase collagen, but until now the underlying mechanisms are not understood in detail."

Dr. Helbig and colleagues conducted a review of peer-reviewed dermatologic and other scientific literature, adding data that involved investigating heat shock response in a human skin explant model. Skin explants were treated once with a 585 nm and 635 nm LED, both from Quantel Medical Derma (France). They compared those either to explants treated with a thermal, ablative fractionated CO₂ laser or thermal, but nonablative, erbium:glass laser and nonirradiated controls.

The researchers showed that both LED irradiations did not lead to upregulations of heat shock protein 70 (HSP70). HSP70 is upregulated in all cells following thermal interventions, as well as other types of physical or chemical stress.

"Following thermal, ablative laser skin rejuvenation therapies, HSP70 is especially upregulated in keratinocytes. This is followed by an upregulation of HSP47 in fibroblasts, leading to increased collagen synthesis. Furthermore, HSP70 obviates apoptosis, limiting cell damage," Dr. Helbig says.

UV'S ROLE Ultraviolet (UV) light exposure causes chronic skin damage when UVA penetrates into the dermis and unleashes molecular and cellular responses. The authors report that matrix metalloproteinases (MMP1, 2, 3, 8, 9 and 13), serine proteases (neutrophil elastase), fibroblast elastase, free radicals and more are induced, damaging dermal collagen and leading to wrinkles.

"In recent findings, we investigated mRNA changes in response to these LED treatments in human fibroblast cultures and compared them to UVA- and UVB-irradiated controls," Dr. Helbig says. "UVA and UVB led to an upregulation of MMP1, whereas collagen 1 and MMP3 expressions were downregulated. In contrast to this, the 585 nm and 635 nm LEDs led to no significant changes of collagen I, MMP1, MMP3, hyaluronic acid synthesizing and degrading enzymes, as well as HSP70 and HSP47 mRNA expressions."

FUTURE COSMETIC INDICATIONS The German researchers' review suggests that there are key future indications of LED in cosmetic practice. According to Dr. Helbig, LEDs seem to have good anti-inflammatory potential.

"Therefore, the technology's use seems to be possible in different inflammatory skin diseases, as well as in wound healing," she says. "LED can be used alone or in combination with other, especially thermal, ablative skin rejuvenation treatments to improve wound healing and reduce downtime."

Disclosures: Dr. Helbig reports no relevant financial interests.