Examining the genomic influence of topically applied probiotics in vitro

Recent work examined the influence of topically applied just-add-water creams containing Lactobacillus plantarum probiotic cultures on to reconstructed human epidermis (RHE). The ability to blend various quiescent probiotic powders in topical systems allows for the examination of these powders on RHEs employing various individual quiescent probiotics using human gene microarrays.

Four topical Just-Add-Water powders (STRATABIOSYS™ Technologies) were prepared containing the following: (1) Lactobacillus plantarum Lp90 [200 M CFU/g]; (2) Saccharomyces cerevisiae [200 M CFU/g]; (3) Streptococcus thermophilus [200 M CFU/g]; and (4) Lactococcus Lactis LLa61 [200 M CFU/g]. A powder without probiotics was used as a placebo control. The creams were prepared by taking 3% of each powder and dissolving it into sterile water. A 15 μL sample of each cream was applied to a RHE tissue that presented approximately 90 K CFU/g of each microorganism on the tissue. The RHE was treated for 24 h with the creams whereupon the residual cream was rinsed off, and the tissues were analysed using Agilent human gene microarrays containing 19 217 individual genes from which a smaller subset of 244 genes pertinent to skin were culled.

The following probiotic specific gene responses were found: (1) Lactobacillus plantarum upregulated 4.9% of the skin-relevant gene set; (2) Saccharomyces cerevisiae upregulated 7.8% of the skin relevant gene set; Streptococcus thermophilus upregulated 6.1% of the skin relevant gene set; Lactococcus lactis upregulated 7.0% of the skin relevant gene set.

A method to examine topical probiotics on RHE has been described that involves converting the powders to preservative-free creams.