Taurine accelerates the synthesis of ceramides and hyaluronic acid in cultured epidermis and dermal fibroblasts.

Taurine is a sulfur-containing amino acid derivative that can be found in the majority of mammalian tissues. Taurine is also present in the skin and is involved in maintaining skin homeostasis by exerting osmoregulatory and antioxidant effects. Previous studies have indicated that taurine treatment is effective against age-, ultraviolet- or detergent-induced skin dysfunction. To determine the mechanism responsible for the beneficial actions of taurine in the skin, the present study aimed to evaluate the effects of taurine on epidermal components (ceramides and filaggrin) and on the dermal extracellular matrix, in three-dimensionally (3D) cultured epidermis and dermal fibroblasts, respectively. These cells were cultured in the presence of 3-50 mM taurine, and cells or culture medium were collected for analysis. The effects of taurine on transepidermal water loss (TEWL) in the skin and the expression of inflammatory cytokines, including IL-1α, IL-1ß and IL-1 receptor antagonist, were investigated in acetone-treated 3D-cultured epidermis using a Tewameter and reverse transcription-quantitative PCR (RT-qPCR), respectively. The mRNA expression levels of MMP-1 and hyaluronic acid (HA) production were measured in skin dermal fibroblasts using RT-qPCR and ELISA, respectively. Taurine was found to suppress acetone-induced elevation in TEWL in 3D-cultured epidermis. Taurine also stimulated the mRNA expression of ceramide synthase 4 and filaggrin, a major structural protein in the stratum corneum, in 3D-cultured epidermis. In skin dermal fibroblasts, taurine inhibited the IL-1α-stimulated mRNA and protein expression of MMP-1. In addition, taurine treatment increased HA synthase-2 mRNA expression and in turn HA production. Results from the present study suggest that the protective effect of taurine on the skin is associated with the enhancement of epidermal barrier component expression and modulation of dermal extracellular matrix metabolism.

[Effects of Skin Environmental Changes by Steam Towel, Ethanol, l-Menthol and Carpronium on the Drug Behavior in the Minoxidil Nanoparticles-applied Mice].

We previously designed the formulation containing minoxidil (MXD) nanoparticles (MXD-NPs), and found that the MXD-NPs can mainly deliver MXD into hair bulbs via hair follicles pathway, and that the therapeutic efficiency for hair growth is higher in comparison with the formulation containing dissolved MXD. In this study, we investigated whether the skin environmental changes by the treatment of steam towel, ethanol, l-menthol and commercially available (CA) carpronium affect the drug behavior in the MXD-NPs-applied mice. The steam towel, ethanol, l-menthol and CA-carpronium were pre-treated 3 min before MXD-NPs application, and the MXD content in the hair bulge, bulb, skin tissue and blood of mice were measured 4 h after MXD-NPs application. No significant difference of MXD levels in the blood was observed by the pre-treatment of steam towel, ethanol, l-menthol and CA-carpronium. On the other hand, the pre-treatment of steam towel and l-menthol enhanced the MXD levels in hair bulge and/or bulb. Although, the MXD levels in hair bulge and bulb were not changed by the pre-treatment of ethanol, the MXD levels in skin tissue was higher than that of saline-pre-treated group (control). The MXD levels in hair bulge, bulb and skin tissue of mice pre-treated with CA-carpronium were remarkably higher in comparison with control. In conclusion, we showed that the changes in skin environment by the steam towel, ethanol, l-menthol and CA-carpronium affected the absorption of MXD-NPs, and these increased MXD levels in the hair bulb and blood by the combination may enhance the therapeutic efficiency without side effects.

Minoxidil Nanoparticles Targeting Hair Follicles Enhance Hair Growth in C57BL/6 Mice.

We previously found that 1% minoxidil (MXD) nanoparticles prepared using a bead mill method led to an increase I n hair follicle delivery and hair growth in C57BL/6 mice. In the present study, we designed a nanoparticle formulation containing 5% MXD (MXD-NPs) using the bead mill method and investigated the hair-growth effect of MXD-NPs and a commercially available MXD solution (CA-MXD). Hair growth and in vivo permeation studies were conducted using C57BL/6 mice. Moreover, we examined the MXD contents in the upper (hair bulge) and the lower hair follicle (hair bulb) and observed the hair follicle epithelial stem cells (HFSC) by immunohistochemical staining using the CD200 antibody. The mean particle size of the MXD in the MXD-NPs was 139.8 nm ± 8.9 nm. The hair-growth effect of the MXD-NPs was higher than that of CA-MXD, and the MXD content in the hair bulge of mice treated with MXD-NPs was 7.4-fold that of the mice treated with CA-MXD. In addition, the activation of HFSC was observed around the bulge in the MXD-NPs-treated mice. We showed that MXD-NPs enable the accumulation of MXD in the upper hair follicles more efficiently than CA-MXD, leading the activation of HFSC and the hair growth.

Development of Artificial-Sebum-Containing Leeming and Notman Agar Medium to Enhance the Growth of Malassezia.

Modified Leeming and Notman agar medium (mLNA) has been widely utilized to grow lipophilic fungi belonging to the genus Malassezia. We developed a new artificial-sebum-containing mLNA to obtain higher yields of Malassezia species. The olive oil in mLNA was replaced with an artificial sebum composed of triglyceride (triolein), diglyceride (glyceryl distearate), fatty acids (palmitic acid, myristic acid, pentadecanoic acid, and oleic acid), and squalene. Furthermore, the Tween 60 was replaced with self-emulsifying glyceryl stearate. Nine human-associated Malassezia species grew well on the artificial-sebum-containing mLNA, and the most predominant fungus on human skin, Malassezia restricta, exhibited double wet cell weight in artificial sebum-containing mLNA compared to wet cell weight in standard mLNA.

Short sequence repeats of the intergenic spacer regions of ribosomal RNA genes in Malassezia globosa and Malassezia restricta colonizing the scalps of male individuals with and without androgenetic alopecia.

We analyzed the short sequence repeats (SSRs) of the intergenic spacer (IGS) region 1 of the ribosomal RNA genes in Malassezia globosa and Malassezia restricta, which predominantly colonize the scalp in androgenetic alopecia (AGA). No AGA-specific SSRs were found in the M. globosa IGS region, whereas a (CT)6 :(AT)8 SSR was predominantly detected in the M. restricta IGS region in the AGA group. Malassezia colonization was higher in the scalps of patients with M. restricta (CT)6 :(AT)8 SSRs than in the scalps of patients without M. restricta (CT)6 :(AT)8 SSRs. These observations suggest that this specific SSR type in M. restricta is involved in the development or exacerbation of AGA.

Scalp Microbiome and Sebum Composition in Japanese Male Individuals with and without Androgenetic Alopecia.

The skin microbiome and sebum may be associated with inflammation-related diseases of the scalp. To assess the pathogenesis and progression of androgenetic alopecia (AGA), we analyzed the composition of sebum and the bacterial and fungal microbiomes of the scalps of 118 Japanese male individuals with and without AGA, then discussed their roles in the pathogenesis of AGA. Sebum triglyceride and palmitic acid contents were higher in the AGA group than in the non-AGA group. Malassezia restricta, a lipophilic fungus that consumes palmitic acid, was abundant on the scalps of patients with AGA. Cutibacterium, Corynebacterium, and Staphylococcus were the most common genera in both groups, and patients with AGA exhibited scalp dysbiosis (increased abundance of Cutibacterium and decreased abundance of Corynebacterium). Our findings suggest that both sebum and the bacterial and fungal microbiomes of the scalp may be involved in the development of AGA.

Protective effect of taurine on UVB-induced skin aging in hairless mice.

Taurine, a sulfur-containing amino acid derivative, exists at a high concentration in the skin and is considered to play an important role in maintaining moisture homeostasis. This study investigated the effects of oral taurine supplementation on epidermal moisture content and wrinkle formation, as well as skin taurine content, using ultraviolet B (UVB)-irradiated hairless mice. Wrinkles were induced by exposing hairless mice to UVB radiation (70-100 mJ/cm2). Taurine was dissolved in drinking water at a concentration of 0.3 or 3% (w/v) and given to the mice ad libitum for 2-10 weeks. Taurine was then extracted from the dorsal skin, and the skin taurine content was determined using high-performance liquid chromatography (HPLC). The wrinkles were evaluated using a wrinkle score and the quantitative wrinkle area ratio. The exposure of the mice to UVB radiation for 4 weeks resulted in a decreased moisture content and increased transepidermal water loss (TEWL) in the skin, while taurine supplementation suppressed these changes. Oral supplementation with taurine for 8 weeks ameliorated the development of UVB-induced wrinkle formation. Furthermore, oral taurine supplementation for 4 weeks decreased pre-stablished wrinkles in a dose-dependent manner. Although the UVB radiation reduced the epidermal taurine content, oral taurine supplementation partly restored the taurine content in the epidermis. The present study showed that oral taurine supplementation is able to suppress UVB-induced wrinkle formation, which may be associated with the regulation of moisture content in the epidermis. The beneficial effects of taurine on skin aging may be attributed to its osmoregulatory role.

Age-related decline in the taurine content of the skin in rodents.

Taurine, a sulfur-containing amino acid, occurs at high concentrations in the skin, and plays a role in maintaining the homeostasis of the skin. We investigated the effects of aging on the content and localization of taurine in the skin of mice and rats. Taurine was extracted from the skin samples of hairless mice and Sprague Dawley rats, and the taurine content of the skin was determined by high-performance liquid chromatography (HPLC). The results of the investigation revealed that the taurine content in both the dermis and epidermis of hairless mice declined significantly with age. Similar age-related decline in the skin taurine content was also observed in rats. In contrast, the taurine content in the sole remained unchanged with age. An immunohistochemical analysis also revealed a decreased skin taurine content in aged animals compared with younger animals, although no significant differences in the localization of taurine were observed between the two age groups. Supplementation of the drinking water of aged mice with 3% (w/v) taurine for 4 weeks increased the taurine content of the epidermis, but not the dermis. The present study showed for the first time that the taurine content of the skin decreased with age in mice and rats, which may be related to the impairment of the skin homeostasis observed with aging. The decreased taurine content of the epidermis in aged animals was able to be rescued by taurine supplementation.

Drug Delivery System Based On Minoxidil Nanoparticles Promotes Hair Growth In C57BL/6 Mice.

PURPOSE: We designed formulations based on minoxidil (MXD) nanoparticles (N-MXD) and examined whether N-MXD can increase drug delivery into the follicles. In addition, we investigated the effect of N-MXD on hair growth in C57BL/6 mice. METHODS: N-MXD (1%) was prepared as follows: methylcellulose, p-hydroxyalkylbenzoates, mannitol, and MXD were dispersed in purified water and milled using zirconia beads under refrigeration (5500 rpm, 30 s×15 times, intermittent milling). C57BL/6 mice were used to evaluate hair-growth effects. The expression levels of mRNA and protein for vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1) were determined by real-time PCR and ELISA methods, respectively. RESULTS: The ratio of solid-MXD was approximately 60% in N-MXD, and the MXD nanoparticles (90-300 nm) were oblong in shape. For the design of nanomedicines, usability is important. Therefore, we measured the stability and toxicity after N-MXD treatment. No agglutination of MXD nanoparticles was detected for 2 weeks, and no redness or MXD powder residue was observed in the skin after repetitive applications of N-MXD. Next, we evaluated hair-growth effects by N-MXD treatment. MXD contents in the skin tissue from N-MXD were lower than for commercially available MXD formulations (CA-MXD). Conversely, MXD contents in the hair bulbs were higher for N-MXD than for CA-MXD, and the drug efficacy of N-MXD was also higher than that of CA-MXD. In addition, the mRNA and protein levels of IGF-1 and VEGF were enhanced by the repetitive application of N-MXD and CA-MXD, and the enhanced IGF-1 and VEGF levels were significantly higher for N-MXD than for CA-MXD. CONCLUSION: We designed a novel nanomedicine based on MXD nanoparticles and showed that N-MXD can deliver MXD into hair bulbs via hair follicles and that the therapeutic efficiency for hair growth is higher than for CA-MXD (solution type).