Study: Niacinamide can restore healthy metabolism of dermal cells

The skin is the largest organ of the human body and protects the body from environmental stresses such as solar radiation, industrial pollution, fossil fuels and carbon emissions. Due to the cumulative damage caused by these external pressures, the changes in cells and structures are intensified, and the skin tissue is very prone to premature aging, affecting the overall function, homeostasis and appearance. Therefore, it is meaningful to understand these changes to determine the mechanisms that can prevent premature aging and maintain skin health and appearance.

One of the signs of aging in many tissues is changes in metabolic processes, especially mitochondrial dysfunction. This change can Lead to a reduction in bioenergy production and transfer and/or reprogramming to compensation pathways, depending on cell type and age/disease conditions. In view of the key role of mitochondria in metabolic output, and the discovery that environmental stressors lead to reduced energy output, especially in the case of damage accumulation in fibroblasts, the impact of aging on mitochondria is worthy of attention.

In order to study the effects of aging on skin metabolism, existing studies have analyzed the gene expression profiles of biopsy samples collected from light-exposed upper facial cheeks and dorsal forearms, and light-protected buttocks. The researchers focused their analysis on the dermal compartment, because overall mitochondrial damage to the skin has been found to be more common and measurable in dermal fibroblasts, partly because of their more static phenotype, which is related to epidermal keratinocytes. In contrast, their proliferation rate is slower. In order to better understand these changes at a functional level, the researchers used primary dermal fibroblast cell banks from donors of different ages to assess the effect of age on cell metabolism.

In order to better understand these metabolic changes that occur with age, researchers recently published an article in the journal Aging Cell, which examined the expression patterns of dermal genes in facial, forearm and buttocks biopsy samples from women aged 20-70. In-depth analysis, these genes encode all the subunits that make up the mitochondrial electron transport chain complex IV. This supplements the previous preliminary analysis of these changes.

"Oxidative phosphorylation" is the most important canonical pathway related to facial aging. The expression patterns of genes encoding many subunits decline with age. The investigation of fibroblasts from elderly donors also showed that compared with young cells, the gene expression, oxidative phosphorylation efficiency, spare respiration capacity, mitochondrial number, and membrane potential of many subunits from complex IV decreased .

The researchers also found that the treatment of old fibroblasts with Nicotinamide (NAM) can restore these indicators to the level of young cells. Nam increases the activity of complexes I, IV and V and the gene expression of representative subunits.

The increase of mt-Keima staining also indicates that the possible mechanism of these recovery effects is the enhancement of mitochondrial autophagy. In addition, Nam also improved the number of mitochondria and membrane potential of young fibroblasts.

These findings indicate that mitochondrial function changes significantly with age, and Nam treatment can restore the bioenergy efficiency and capacity of elderly fibroblasts.