Short communication: Effects of Lactobacillus helveticus-fermented milk on the differentiation of cultured normal human epidermal keratinocytes.

Effects of Lactobacillus helveticus-fermented milk whey on the differentiation of normal human epidermal keratinocytes were studied. Analysis using real-time reverse transcription-polymerase chain reaction revealed that addition of Lactobacillus helveticus-fermented milk whey to the culture medium enhanced mRNA expression of keratin 10, an early differentiation marker, as well as involucrin, a late differentiation marker. Whey of artificially acidified milk, prepared by the addition of dl-lactic acid to milk instead of fermentation, also promoted expression of both markers, but Lactobacillus helveticus-fermented milk whey was more effective in increasing expression of those markers. These results indicate that milk whey has the potential to induce multiple stages of keratinocyte differentiation and that fermentation with Lactobacillus helveticus increases that activity. Furthermore, we examined the expression of profilaggrin, which increases with epidermal terminal differentiation, and found that Lactobacillus helveticus-fermented milk whey enhanced expression of profilaggrin mRNA in a dose-dependent manner. Expression also occurred to a greater extent than with artificially acidified milk whey or other whey samples prepared with several lactic acid bacterial species. Because the proteolytically processed form of profilaggrin, filaggrin, is very important for normal epidermal hydration and flexibility, our results indicate that Lactobacillus helveticus-fermented milk whey has the potential to enhance the production of filaggrin-related natural moisturizing factor, because of its effect on the induction of epidermal differentiation, and is expected to be a useful skin moisturizing agent.