Author(s)

Kukizo Miyamoto^1*, Yoko Munakata¹, Keisuke Fujii¹, Chenlu Lei¹, Ley Yang², Suda Sudarsana¹, Masutaka Furue³

¹Research and Development, Kobe Innovation Center, Procter and Gamble Innovation GK, Kobe, Japan.
²Global Scientific Communications, P & G Guangzhou Ltd., Guangzhou, China.
³Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.

Background: Aged skin exhibits visual alterations such as wrinkles, rough texture, pore dilation, and dull skin tone, as well as physiological aging, namely, decreased hydration and increased transepidermal water loss (TEWL). Recent advances in coherence tomography have also revealed that skin aging affects in vivo epidermal keratinocyte architecture. However, the interconnectivity between spatial architectural aging and visual/physiological aging parameters remains largely unknown. Purpose: To elucidate whether the tomographic keratinocyte architectural aging is correlated with visual and physiological skin aging parameters and to quantitatively evaluate the improvements of the architectural, visual, and physiological aging parameters by the daily treatment of the skin care formula containing Galactomyces Ferment Filtrate (GFF, 8X Pitera^TM). Method: We measured the in vivo keratinocyte cellular architecture with two-photon stereoscopic tomography obtaining by-layer epidermal section images in 78 Asian females of various ages. Visual aging parameters were analyzed using a portable image capture system. Hydration and TEWL were also assessed. The anti-aging effects of GFF-containing skin moisturizer (SK-II LXP Cream^TM) were also examined in two studies after twice-daily application for 2 (N = 35) and 4 (N = 32) weeks. Results: As for the keratinocyte cellular architecture, skin aging was significantly associated with decreased cell density and increased cell uniformity. These architectural aging parameters were significantly correlated with visual and physiological aging parameters, namely, rough texture, wrinkles, pore dilation, dull skin tone, dehydration, and increased TEWL. The strong interconnectivity allowed us to develop formulae to estimate the keratinocyte architecture from visual aging parameters. Moreover, twice-daily application of SK-II significantly improved the keratinocyte architecture associated with multiple skin aging visual and physiological parameters. Conclusion: Skin aging is a process involving mutual interconnections among epidermal keratinocyte cellular architecture, visual, and physiological parameters. The GFF-containing moisturizer SK-II effectively improves spatial architecture of keratinocytes in epidermis and these evaluated skin aging parameters in a new trajectory over the course of treatment.

Facial Skin Aging, In Vivo Keratinocyte Cellular Architecture, Visual Aging Pa-rameter, Dehydration, Interconnectivity, New Trajectory, Galactomyces Fer-ment Filtrate, PiteraTM, SK-II LXP CreamTM

Miyamoto, K. , Munakata, Y. , Fujii, K. , Lei, C. , Yang, L. , Sudarsana, S. and Furue, M. (2024) Quantification of In Vivo Epidermal Keratinocyte Architecture Associated with the Signs of Skin Aging and the Skin Benefit Evaluation by Application of Galactomyces Ferment Filtrate (Pitera)-Containing Skin Care Product. Journal of Cosmetics, Dermatological Sciences and Applications, 14, 12-28. doi: 10.4236/jcdsa.2024.141002.