Clinical profiling of skin microbiome and metabolome during re-epithelialization.

We investigated changes in skin microbiome and metabolome linked to wound healing and how these are affected by a formula known to improve re-epithelialization. In a clinical study with 21 subjects, forearm lesions were induced by epidermal laser ablation. The areas were left untreated or treated with the formula. Re-epithelialization was monitored for 18 days. Skin swabs were analyzed for microbiome diversity using 16 S rRNA gene sequence analysis. Selected species analyzed using digital droplet polymerase chain reaction. Metabolomic profiles were analyzed by ultra-high performance liquid chromatography-high-resolution mass spectrometry. Microbiota alpha-diversity (richness and evenness) was markedly reduced by laser ablation and returned to pre-ablation levels on Day 5. Formula application accelerated the re-epithelialization time (RT), which was more efficient for slow healing (RTs of 15-19 days) than quick healing (10-12 day RTs) subjects. The repairing effect was associated with greater microbiota diversity and species-specific growth of commensal bacteria. Levels of several metabolites on untreated skin at the RT and the extent of the impact of the formula were different in slow and quick healers. The formula significantly modified the skin metabolome, whereby metabolites involved in promoting wound healing were increased and metabolites consumed by the commensal bacteria were decreased.