Vitamin D Protection Against Acute UV Damage: A Critical Role of Autophagy in the Skin

The study from April 30, 2016, examined the role of vitamin D in suppressing UV-induced skin inflammatory responses. The research involved mouse models and a blinded placebo-controlled trial of 20 human subjects. The key findings were that a single high dose of oral vitamin D reduced UV-induced skin erythema and improved histological features from skin biopsies. This was associated with a significant decrease in TNFα expression, a 3-fold decrease in iNOS, and a 3-fold increase in LC3+ cells, a marker for autophagy. The results suggest that vitamin D ameliorates UV-induced inflammation by suppressing macrophage activation through the modulation of autophagy. Parallel studies in UV-exposed mice confirmed an inverse correlation between inflammation and vitamin D-enhanced autophagy. This introduced a new paradigm in immune response in skin injury, suggesting that vitamin D's ability to enhance cell "fitness" by upregulating autophagy could be translated for clinical use in skin repair.