Does blue light restore human epidermal barrier function via activation of Opsin during cutaneous wound healing?

Abstract

Opsins are expressed in the epidermis and dermis of human skin and in the newly regenerating epidermis following wounding. An increase in OPN3 expression in the epithelial tongue may be a potential mechanism for the stimulation of wound closure by blue light. Since keratinocytes and fibroblasts retain their expression of Opsins in culture, they provide a good model to investigate the mechanism of blue light in wound healing responses. Knockdown of OPN3 led to a reduction in early differentiation of keratinocytes following irradiation with blue light, suggesting OPN3 is required for restoration of the barrier function. Understanding the function and relationship of different photoreceptors and their response to specific light parameters will lead to the development of reliable light-based therapies for cutaneous wound healing. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc.

The expression of opsins in the human skin and its implications for photobiomodulation: A Systematic Review

“…They found that low levels of blue light did not affect migration or proliferation, but stimulated differentiation of keratinocytes, which was abrogated by OPN3 knockdown. Overall, the current findings on keratinocytes suggest that OPN3 is involved in cell differentiation regulation and restoration of the barrier function 54 …”

“…In 2018, Pellicena et al reported for the first time that cultured dermal fibroblasts from human facial and abdominal skin tissue express OPN1‐SW, OPN2, and OPN3 54 . Although the function of these opsins in dermal fibroblasts was not elucidated in their study, they inferred from the previous finding showing the anti‐proliferative effect of blue light (450‐490 nm) on fibroblasts in vitro that opsins might be involved in the regulation of cell proliferation 61‐63 .…”

“…In 2018, Pellicena et al confirmed the expression of OPN1‐SW, OPN3, and OPN5 in cultured epidermal keratinocytes of human facial and abdominal skin by immunofluorescence analysis and also showed that irradiation with blue light (447 nm) accelerates wound closure in the regenerating epithelial tongue of an ex vivo human skin wound‐healing model with a corresponding increase in OPN3 expression 54 . To further explore how OPN3 mediates wound healing, they evaluated the migration, proliferation, and differentiation, which are vital for wound repair, in cultured keratinocytes following blue light irradiation.…”

Effects of red light on inflammation and skin barrier recovery following acute perturbation. Pilot study results in healthy human subjects

“…The choice of the higher fluence (30 J/cm 2 ) stemmed from a study which showed that red light at 656 nm stimulated metabolic activity of primary human epidermal keratinocytes in vitro and increased wound closure ex vivo . 2 The choice of the lower fluence (3.2J/cm 2 ) was guided by previous work where 4 J/cm 2 accelerated migration of oral keratinocytes in vitro 3 and promoted healing of venous ulcers in humans. 4 No differences between the two groups were present with respect to age and Fitzpatrick skin type (I-III).…”

“…This is in contrast with previous data which showed a stimulatory effect of red light. 2,8,9 Enhanced skin barrier recovery might have been obtained with repeated irradiations instead of a single irradiation. A delaying effect of blue light on the recovery of the skin barrier was instead observed with a single irradiation with blue light.…”