Probiotics for photoprotection

Abstract

Specific strains of probiotic, have been identified as beneficial to influence the composition and/or metabolic activity of the endogenous microbiota and some of these strains have been also shown to inhibit the growth of a wide range of enteropathogens. The first aim of using probiotics has been to improve the composition of the intestinal microbiota from a potentially harmful composition towards a composition that would be beneficial to the host.Beyond their capacity to influence positively the composition of the intestinal microbiota, several lines of evidence suggest that some probiotic bacteria can modulate the immune system both at the local and systemic levels thereby improving immune defense mechanisms and/or downregulate immune disorders such as allergies or intestinal inflammation.Skin reflects the general health status and aging. Different human trials widely suggest that probiotic supplementation might be useful in the management of atopic dermatitis. Based on these properties it appears that, beyond the gut, probiotics might exert their benefits at the skin level.In a randomized double blind placebo-controlled clinical trial, we investigated whether the probiotic bacteria Lactobacillus johnsonii NCC 533 (La1) could modulate the cutaneous immune homeostasis altered by solar-simulated UV exposure in humans. After, UV exposure to twice 1.5 MED, we demonstrated that La1 intake facilitated an earlier recovery of Epidermal cells allostimulatory function. Thus, this clinical data strengthen the assumption that certain probiotics can contribute to modulate skin immune system leading to the preservation of the skin homeostasis. Altogether the data affords the possibility of designing new strategies based on a nutritional approach for the prevention of UV-induced damaging effects.

Keywords: Lactobacillus johnsonii; food supplement; immune homeostasis; photoprotection; probiotics; skin; stress.

Figure 1

Study protocol: schematic representation of the exposed and non-exposed buttock areas used for MED determination, biopsy and blister collection. D0 is Day 0 of the study before the start of La1 supplementation, D57, D60 and D66 are Day 1, 4 and 10 after UV exposure, respectively.

Figure 2

Representative immunohistochemical staining for three antigens, before treatment (BT) or on different days after UV exposure. Bars = 100 µm.

Figure 3

Results from MECLR: mean cpm ratios from exposed versus non-exposed skin samples. The ratios were calculated from the 54 volunteers (A) or from the UV-sensitive (UVS) and UV-resistant (UVR) subjects (B) distributed among the La1 and placebo groups. *** Statistically significant differences at p < 0.001; ** statistically significant differences at p < 0.01; * statistically significant differences at p < 0.05 between exposed and non-exposed sides. BT: before treatment.