Physiological Skin Characteristics of Infants and Children Compared to Those of Women.

Introduction There is little information regarding skin conditions in infants and children, especially with respect to age, anatomical sites, and seasonal variations. This study aimed to compare the physiological skin characteristics of infants and children with those of women. Methods This study involved skin measurements and a questionnaire-based survey assessing healthy infants and children aged one month to six years and four months (37 males and 48 females) and 15 healthy women in their twenties in the summer, and healthy infants and children aged two months to six years and seven months (34 males and 45 females) and 15 healthy women in their twenties in the winter. The physiological characteristics of the skin of infants and children were surveyed by age. We excluded infants and children with allergic symptoms at the time of measurement. There were 11 subjects with a history of atopic dermatitis. Results Compared with women, infants and children had lower stratum corneum water content and higher transepidermal water loss (TEWL) at most sites. Minimal sebum secretion was observed throughout the body in infants and children aged ≥1 year. The skin surface pH of infants and children was low throughout the body. The questionnaire revealed that skin issues were most common at the anterior neck and cubital fossa, where TEWL was markedly high. These results suggest that barrier function is less developed in the skin of infants and children than in the skin of women. Conclusions The physiological characteristics of skin varied depending on age, anatomical site, and season; hence, skincare guidance must be provided according to these factors.

Investigation of partially myristoylated carboxymethyl chitosan, an amphoteric-amphiphilic chitosan derivative, as a new material for cosmetic and dermal application.

BACKGROUND: Cationic amphiphilic chitosan derivatives can form polymeric micelles, which are useful cosmetic materials, but they form polyion complexes with anionic polymers, which can cause formulation difficulties. AIMS: This study aimed to evaluate the usefulness of partially myristoylated carboxymethyl chitosan, an amphoteric-amphiphilic chitosan derivative, as a new material for cosmetics in the absence of a surfactant comprising an anionic polymer. METHODS: An anionic polymer and 1,2-decanediol (an antimicrobial agent)-containing partially myristoylated carboxymethyl chitosan nanoemulsified lotion and glabridin (an antimelanogenic agent)-containing partially myristoylated carboxymethyl chitosan polymeric micelle were prepared using a pressure homogenization method. The release of interleukin-1α, cell viability, and melanogenesis inhibition was evaluated on a human skin model. Antimicrobial activity was evaluated using agar dilution method. RESULTS: A mixture of partially myristoylated carboxymethyl chitosan and carboxyvinyl polymer did not form a polyion complex, but it formed a hydrophilic gel. The anionic polymer-containing partially myristoylated carboxymethyl chitosan nanoemulsified formulation was stable, with no decrease in cell viability and horny layer exfoliation, which are typically observed with Tween 60. Compared with the formulation with methyl paraben (0.2%), the formulation to which 1,2-decanediol (0.05%) was added improved the antibacterial activity against methicillin-resistant Staphylococcus aureus and Propionibacterium acnes; however, no interleukin-1α upregulation was observed. The glabridin-containing partially myristoylated carboxymethyl chitosan polymeric micelles enhanced melanogenesis inhibition and percutaneous glabridin delivery to the epidermis compared with conventional emulsified micelles. CONCLUSIONS: These results suggest that partially myristoylated carboxymethyl chitosan-forming polymeric micelles, in combination with 1,2-decanediol and glabridin, may be useful for surfactant-free cosmetic emulsions.

Efficient Percutaneous Delivery of the Antimelanogenic Agent Glabridin Using Cationic Amphiphilic Chitosan Micelles.

Partially myristoylated chitosan pyrrolidone carboxylate (PMCP) is a cationic amphiphilic chitosan derivative. Glabridin (Glab) from licorice root extracts is a hydrophobic antimelanogenic agent. Here we assessed the effects of cationic Glab-containing polymeric micelles derived from PMCP (Glab/PMCP-PM) on the ability of Glab to penetrate the skin and inhibit melanogenesis using a human skin model. The amount of Glab absorbed 24 h after the application of Glab/PMCP-PM was approximately four times higher than that of conventional oil-in-water micelles (control) prepared using Tween 60. Further, the release of IL-1α, a mediator of inflammation, was not detected. Treatment with Glab/PMCP-PM significantly increased the inhibition of melanogenesis compared with control. The inhibition of melanogenesis depends upon the enhanced ability of Glab to penetrate the skin, particularly the epidermis. Moreover, the inhibition of melanogenesis and the cationic potential of the Glab/PMCP-PM levels were increased by the cationic phospholipid copolymer. Therefore, Glab/PMCP-PM shows potential as an effective transdermal delivery system for treating skin hyperpigmentation.

Cinnamtannin B-1 Promotes Migration of Mesenchymal Stem Cells and Accelerates Wound Healing in Mice.

Substances that enhance the migration of mesenchymal stem cells to damaged sites have the potential to improve the effectiveness of tissue repair. We previously found that ethanol extracts of Mallotus philippinensis bark promoted migration of mesenchymal stem cells and improved wound healing in a mouse model. We also demonstrated that bark extracts contain cinnamtannin B-1, a flavonoid with in vitro migratory activity against mesenchymal stem cells. However, the in vivo effects of cinnamtannin B-1 on the migration of mesenchymal stem cells and underlying mechanism of this action remain unknown. Therefore, we examined the effects of cinnamtannin B-1 on in vivo migration of mesenchymal stem cells and wound healing in mice. In addition, we characterized cinnamtannin B-1-induced migration of mesenchymal stem cells pharmacologically and structurally. The mobilization of endogenous mesenchymal stem cells into the blood circulation was enhanced in cinnamtannin B-1-treated mice as shown by flow cytometric analysis of peripheral blood cells. Whole animal imaging analysis using luciferase-expressing mesenchymal stem cells as a tracer revealed that cinnamtannin B-1 increased the homing of mesenchymal stem cells to wounds and accelerated healing in a diabetic mouse model. Additionally, the cinnamtannin B-1-induced migration of mesenchymal stem cells was pharmacologically susceptible to inhibitors of phosphatidylinositol 3-kinase, phospholipase C, lipoxygenase, and purines. Furthermore, biflavonoids with similar structural features to cinnamtannin B-1 also augmented the migration of mesenchymal stem cells by similar pharmacological mechanisms. These results demonstrate that cinnamtannin B-1 promoted mesenchymal stem cell migration in vivo and improved wound healing in mice. Furthermore, the results reveal that cinnamtannin B-1-induced migration of mesenchymal stem cells may be mediated by specific signaling pathways, and the flavonoid skeleton may be relevant to its effects on mesenchymal stem cell migration.

Mallotus philippinensis bark extracts promote preferential migration of mesenchymal stem cells and improve wound healing in mice.

In the present study, we report the effects of the ethanol extract from Mallotus philippinensis bark (EMPB) on mesenchymal stem cell (MSC) proliferation, migration, and wound healing in vitro and in a mouse model. Chemotaxis assays demonstrated that EMPB acted an MSC chemoattractant and that the main chemotactic activity of EMPB may be due to the effects of cinnamtannin B-1. Flow cytometric analysis of peripheral blood mononuclear cells in EMPB-injected mice indicated that EMPB enhanced the mobilization of endogenous MSCs into blood circulation. Bioluminescent whole-animal imaging of luciferase-expressing MSCs revealed that EMPB augmented the homing of MSCs to wounds. In addition, the efficacy of EMPB on migration of MSCs was higher than that of other skin cell types, and EMPB treatment improved of wound healing in a diabetic mouse model. The histopathological characteristics demonstrated that the effects of EMPB treatment resembled MSC-induced tissue repair. Taken together, these results suggested that EMPB activated the mobilization and homing of MSCs to wounds and that enhancement of MSC migration may improve wound healing.