-Hydroxycinnamic Acid Mitigates Senescence and Inflammaging in Human Skin Models.

-hydroxycinnamic acid (pHCA) is one of the most abundant naturally occurring hydroxycinnamic acids, a class of chemistries known for their antioxidant properties. In this study, we evaluated the impact of pHCA on different parameters of skin aging in in vitro skin models after HO and UV exposure. These parameters include keratinocyte senescence and differentiation, inflammation, and energy metabolism, as well as the underlying molecular mechanisms.

Integration of transcriptomics and spatial biology analyses reveals Galactomyces ferment filtrate promotes epidermal interconnectivity via induction of keratinocyte differentiation, proliferation and cellular bioenergetics.

Objective: Human skin is the first line of defence from environmental factors such as solar radiation and is susceptible to premature ageing, including a disruption in epidermal differentiation and homeostasis. We evaluated the impact of a Galactomyces Ferment Filtrate (GFF) on epidermal differentiation and response to oxidative stress.

Methods: We used transcriptomics, both spatial and traditional, to assess the impact of GFF on epidermal biology and homeostasis in keratinocytes (primary or immortalized) and in ex vivo skin explant tissue.

Nicotinamide Prevents UVB- and Oxidative Stress‒Induced Photoaging in Human Primary Keratinocytes.

Nicotinamide (NAM), a NAM adenine dinucleotide precursor, is known for its benefits to skin health. Under standard culture conditions, NAM delays the differentiation and enhances the proliferation of human primary keratinocytes, leading to the maintenance of stem cells. In this study, we investigated the effects of NAM on photoaging in two-dimensional human primary keratinocyte cultures and three-dimensional organotypic epidermal models.

Metabolic dysfunction in human skin: Restoration of mitochondrial integrity and metabolic output by nicotinamide (niacinamide) in primary dermal fibroblasts from older aged donors.

Alterations in metabolism in skin are accelerated by environmental stressors such as solar radiation, leading to premature aging. The impact of aging on mitochondria is of interest given their critical role for metabolic output and the finding that environmental stressors cause lowered energy output, particularly in fibroblasts where damage accumulates. To better understand these metabolic changes with aging, we performed an in-depth profiling of the expression patterns of dermal genes in face, forearm, and buttock biopsies from females of 20-70 years of age that encode for all subunits comprising complexes I-V of the mitochondrial electron transport chain.

Nicotinamide Metabolism Modulates the Proliferation/Differentiation Balance and Senescence of Human Primary Keratinocytes.

Nicotinamide (NAM) is the main precursor of nicotinamide adenine dinucleotide (NAD), a coenzyme essential for DNA repair, glycolysis, and oxidative phosphorylation. NAM has anti-aging activity on human skin, but the underlying mechanisms of action are unclear. Using 3-dimensional organotypic skin models, we show that NAM inhibits differentiation of the upper epidermal layers and maintains proliferation in the basal layer.