Six Amino Acids among Natural Moisturizing Factors Responsible for Skin Hydration: Improvement and Anti-Aging of Skin by Galactomyces Ferment Filtrate-PiteraTM Containing Skin Moisturizer

Background: Natural moisturizing factors (NMFs) are filaggrin-derived components in the cornified layer that are critical for maintaining healthy skin moisturization and barrier function. However, studies have reported conflicting findings on the relationship between NMF levels and aging, while few studies have investigated this relationship clinically. To fill this research gap, we determined the levels of major NMF components such as free amino acids, pyrrolidone carboxylic acid, and urocanic acids, and individually verified their relationships with skin hydration, barrier function, age, and skin aging. Purpose: The objective of this study was to clinically investigate the relationship between NMF components levels and skin aging in facial skin. The main NMF components were obtained from facial skin and quantified. We then selected NMF components showing strong relationships to skin hydration, and analyzed the relationships of the levels of these selected NMF components with signs of skin aging, namely, texture, pores, wrinkles, and dullness (L-value). We also examined the efficacy of treatment with a skin care formula (SK-II Facial Treatment Essence, called SK-II FTE hereafter) including Galactomyces ferment filtrate (GFF, PiteraTM) on the selected NMF component levels associated with skin hydration and barrier function, and the signs of skin aging of texture, pores, wrinkles, and dullness (L-value). Method: We conducted two clinical trials in this research. In Study 1, we measured 23 NMF components using tape-stripped cornified layer to quantify them via an HPLC method in 196 Asian females aged 20 to 59 (mean S.D., 38.6 9.4). Facial visual aging parameters [texture, pores, wrinkles, and dullness (L-value)], as well as elasticity (R7), skin hydration, and TEWL, were quantified using facial skin imaging and skin physical property measurement devices. Study 2 was performed to evaluate whether the facial application of SK-II FTE affects the NMF levels and skin aging parameters in 63 Asian female volunteers aged 20 to 55 (38.4 9.03). During the course of Study 2, 0.6 mL of SK-II FTE was applied to the face twice daily in the morning and afternoon. Skin measurements were performed at the start of the day (baseline) and at week 8. Results: In Study 1, we examined the stratum corneum levels of 23 NMF components comparing to the skin hydration status in 196 female subjects. The subjects were divided into two groups using the median of each measured NMF component. Skin hydration values were compared between the two groups defined for each NMF component. The results showed that subjects with higher levels of six amino acids, alanine, arginine, asparagine, glutamine, glycine, and histidine, exhibited significantly higher skin hydration than those with lower amino acid levels. No significant differences in skin hydration values were found for the other 17 NMF components. We then analyzed whether the sum of these six amino acid NMF components (called 6-AA-NMFs, hereafter) is affected by aging. The 6-AA-NMF level peaked in the subjects aged 25-29, and then gradually and significantly decreased with age. Interestingly, the 6-AA-NMF level was significantly correlated with the skin hydration value, but not with TEWL. In addition, the 6-AA-NMF level demonstrated significant correlations with the signs of skin aging of texture, pores, wrinkles, and dullness (L-value). Then, in Study 2, we examined whether the daily application of SK-II FTE affects the 6-AA-NMF level and visual aging parameters in 63 females. SK-II FTE demonstrated significant increases of the levels of 6-AA-NMFs and each of its components associated with hydration and barrier function, and improvements of skin texture, pores, wrinkles, and dullness (L-value) during the 8 weeks of treatment of facial skin. Conclusion: These clinical studies with large numbers of subjects across a wide age range revealed that six amino acids as NMF components were highly correlated with facial skin hydration in the stratum corneum. The levels of these six NMF components were also found to decrease at ages after the 30 s and were significantly correlated with major signs of skin aging. Notably, these six NMF components (6-AA-NMFs) were increased by SK-II FTE treatment associated with improvements of skin hydration and signs of skin aging, namely, texture, pores, wrinkles, and dullness (L-value). These studies were limited by the lack of investigation of why some NMF components were not associated with skin hydration. More clinical trials examining various NMF components and their relationship with aging are anticipated.

Study on the Effect and Mechanism of Green Plum Citron Double Strain Fermentation Filtrate on Skin Barrier

To study the effect of Green plum citron double strain fermentation filtrate(DSF)on the proliferation rate of HaCaT keratinocytes by CCK8 assay.The effect of DSF on the mRNA transcription levels of filagolin(FLG),loricrin(LOR),and occludin 1(CLD1)in HaCaT cells in sodium dodecyl sulfate(SLS)model was investigated by qPCR.The effect of DSF on the content of TNF-αin the supernatant of HaCaT cells in the model was investigated by Elisa.The results showed that DSF had no toxicity to HaCaT cells,but it could increase the mRNA transcription levels of FLG,LOR and CLD1 in HaCaT cells in the model,and reduce the content of TNF-αin the supernatant of HaCaT cells in the model.DSF had a certain effect on skin care of strengthening skin barrier.

Expanded Follicle-Sulcus-Crack Complex Is an Early Warning Sign of Facial Skin Aging: Improvement by Application of Galactomyces Ferment Filtrate-Containing Skin Product

Background: Wrinkles, pigmented spots, and roughness are representative parameters reflecting facial skin aging. Sulci cutis connecting to follicular orifices frequently form perifollicular cracks, which join together adjacent sulci. This follicle-sulcus-crack complex (FSCC) is exacerbated by dehydration. Purpose: Although dehydration is associated with facial skin aging, FSCC’s implications in facial skin aging remain unresolved. Method: We measured facial skin parameters in 1999 and 2010 in 108 Japanese women, and in 2006 and 2016 in 182 Chinese women. We addressed whether expansion of FSCC is associated with other skin aging parameters. We also examined whether skin moisturizer can reverse the expanded FSCC. Results: In both clinical studies, FSCC severity as well as wrinkles, spots, and roughness significantly deteriorated with age. Notably, FSCC significantly increased as early as in subjects in their 20s, whereas wrinkles, spots, and roughness became conspicuous in those in their 40s or older. Moreover, subjects with more severe FSCC in the initial measurement exhibited significantly worse wrinkles, spots, and roughness in the second measurement a decade later. Dehydration was significantly correlated with expanded FSCC. Furthermore, FSCC expansion was reversed after appropriate moisturization by daily application of Galactomyces ferment filtrate (GFF)-containing skincare product (SK-II Skin Power Cream) for 4 weeks in 37 women. Conclusion: The expanded FSCC is likely to be an early indicator of facial skin aging. Appropriate moisturization may reduce FSCC formation and decelerate facial skin aging.