Biological Effects of a <i>Bacillus sp</i>. Ferment Extract through the Protection of Key Features Associated with Aging in Human Skin Biopsies

Aging is an inevitable and multifaceted biological process that significantly impacts human skin at various levels, leading to structural and functional changes. These changes include a decline in epidermal stem cell functionality, alterations in the dermal-epidermal junction (DEJ), and the deterioration of the extracellular matrix (ECM). Telocytes, a type of interstitial cell found in the dermis, play a crucial role in maintaining skin health. They are also suggested to be involved in the organization and maintenance of the ECM, and their role in skin aging is currently under investigation. In this study, we used a comprehensive age-induced skin model developed by exposing human skin biopsies to both ultraviolet (UV) irradiation and glycation stress, creating a suitable tool to recapitulate the skin aging features caused by extrinsic and intrinsic factors. Changes in the ECM density and in the organization and integrity at the collagen network level were illustrated using this ex vivo model. Moreover, we validated that the aging process can be delayed by treatment with a newly developed Bacillus sp. ferment extract. The extract improved DEJ integrity and supported the epidermal stem cell niche in skin biopsies from an elderly donor. Furthermore, the protection of ECM features associated with aging conditions after Bacillus sp. treatment was also confirmed. Finally, we demonstrated that the new Bacillus sp. ferment extract increased the number of telocytes in human skin biopsies from an elderly donor and enhanced the proliferation rate of isolated telocytes in culture, providing a hypothetical explanation for its anti-aging mechanism of action.