Kiperin Postbiotic Supplement-Enhanced Bacterial Supernatants Promote Fibroblast Function: Implications for Regenerative Medicine.

Background/Objectives: Kiperin Postbiotics, defined as non-viable metabolic products derived from probiotics, have gained attention as potential modulators of cellular responses involved in tissue repair. This study aimed to evaluate the effects of a postbiotic supplement (PS)-composed of inactivated strains of Escherichia coli, Lacticaseibacillus rhamnosus, and Lactiplantibacillus plantarum-on fibroblast function, particularly in the context of bacterial secretomes from common pathogenic strains. Methods: Human fibroblast cell lines (HFF-1 and CCD-18Co) were treated with cell-free supernatants (CFS) from E. coli ATCC 25922, Staphylococcus aureus ATCC 29213, and Enterococcus faecalis ATCC 29212, either alone or in combination with the PS. Assessments included cell count, migration (via scratch assay), oxidative stress levels, and expression of immune-related genes (IL-6, IL-10, TNF-α, DRD4). Results: CFS from E. faecalis significantly increased fibroblast counts, whereas E. coli and S. aureus CFS reduced cell counts and elevated oxidative stress. Co-treatment with PS reversed these effects in a strain-dependent manner by lowering oxidative stress and partially restoring cell proliferation. Scratch assays demonstrated enhanced migration in PS-treated fibroblasts. Gene expression analyses revealed no statistically significant changes, though variable trends were observed across treatment groups. Conclusions: PS may mitigate the harmful effects of certain bacterial secretomes while preserving or enhancing beneficial ones. Its ability to reduce oxidative stress and promote fibroblast proliferation and migration suggests a potential pro-regenerative role in vitro. Although gene expression changes were limited, the results offer initial insights into the underlying molecular responses influenced by postbiotic supplementation.