Light-emitting diode red light attenuates epidermal thickening and keratinocyte proliferation in psoriasis models.

Psoriasis is an immune-mediated skin condition that impacts approximately 3% of the United States population, with limited adjunctive therapy options. This study investigates the effects of light emitting diode red light (LED-RL) as a potential adjunct. Using in vitro keratinocytes, three-dimensional (3D) recapitulated skin models, and a mouse model, LED-RL's impact on keratinocyte proliferation and epidermal thickness was assessed. Our findings show that LED-RL significantly reduced keratinocyte proliferation without inducing apoptosis, likely through cell cycle modulation and decreased phosphorylation of STAT3, a pathway critical to psoriasis pathogenesis. In the 3D skin models, LED-RL at a dose of 640 J/cm2 reduced epidermal thickness in IL-22-stimulated samples. In mouse models, a daily dose of 1280 J/cm2 decreased epidermal thickness when co-administered and administered following the development of a psoriasiform phenotype with imiquimod. These results suggest LED-RL may offer an efficacious and cost-effective alternative to existing therapies for mild to moderate psoriasis.