Tranexamic Acid Improves the Disrupted Formation of Collagen and Fibrillin-1 Fibers Produced by Fibroblasts Repetitively Irradiated with UVA.

The dermis is mainly constructed by type I collagen fibers, which provide mechanical strength to the skin by building a frame-like structure, and by elastic fibers, which provide elasticity to respond to movements of the skin. The depletion of collagen fibers and the disappearance of oxytalan fibers, which are a type of elastic fiber, are characteristic changes in photoaged skin. Prostaglandin E2 (PGE2) is one of the chemical mediators involved in inflammation and is responsible for sunburn. Furthermore, it has been reported that PGE2 attenuates the production of collagen and the expression of elastic fiber-related factors in fibroblasts. Tranexamic acid (TXA), which is an anti-inflammatory medicine that inhibits plasmin, reduces the level of PGE2 secreted following UV exposure or after inflammatory stimulation. However, few reports have verified TXA as an anti-skin aging agent. In this study, we examined the potential of TXA as an anti-skin aging agent using repetitively UVA-irradiated fibroblasts as a model for fibroblasts located in chronically sun-exposed dermis. Repetitively UVA-irradiated fibroblasts had higher secretion levels of PGE2. In addition, fibroblasts repetitively irradiated with UVA or treated with PGE2 produced disrupted collagen and fibrillin-1 fibers. Treatment with TXA improved the formation of both types of fibers by repetitively UVA-irradiated fibroblasts by restoring the expression of fiber-related proteins at the mRNA and protein levels. Thus, these results demonstrate that TXA has potential as an anti-photoaging agent.

Modification of skin discoloration by a topical treatment containing an extract of Dianella ensifolia: a potent antioxidant.

Skin hyperpigmentation, and the reactions that precipitate it, have been linked to free radicals by the fact that free radical scavengers or antioxidants can slow that hyperpigmentation. We have screened several hundred plant extracts for antioxidants and discovered one that is both a strong antioxidant and can reduce skin hyperpigmentation. Extracts of Dianella ensifolia contain 1-(2,4-dihydrophenyl)-3-(2,4-dimethoxy-3-methylphenyl) propane (DP), which was found to inhibit the free radical 1-1-diphenyl-2-picryl-hydrazyl (DPPH) with an EC(50) value of 78 mum. DP was also found to inhibit Ultraviolet (UV)C-induced lipid oxidation with an EC(50) of about 30 mum. We next investigated the effects of this antioxidant on skin hyperpigmentation. The reduction of discoloration by different topical treatments has been assessed in human volunteers using an in vivo assay for the rate of fading of UVB-induced tan. Two pharmaceutical formulas containing 4% hydroquinone (HQ) were used as positive controls, and we tested the ability of DP, a plant-derived amphoteric antioxidant, to increase performance of non-HQ cosmetic formulations. We found that the cosmetic formula containing DP produced an increase in the rate of fading compared to the two pharmaceutical treatments containing HQ.