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Purpose An increasing number of people are suffering from hair loss disorders. Niacinamide has long been used as an active ingredient for anti-hair loss preparations but the exact mechanism has not been clearly elucidated yet. The effects of niacinamide were investigated in cultured human dermal papilla cells (hDPCs). Methods To investigate the anti-hair loss effect of niacinamide and its molecular mechanisms, Western blot analysis, ELISA, quantitative RT-PCR and immunocytochemistry were performed. To study the protective effects of niacinamide against H2O2-induced oxidative stress, ROS generation and cytotoxicity were evaluated by DCF-DA assay and LDH release assay, respectively. Minoxidil was used as a positive control. Results Niacinamide decreased the protein expression level of DKK-1 which promotes regression of hair follicles by inducing catagen. The protein expression levels of cell senescence markers, p21 (CDKN1A) and p16 (CDKN2A) which are related to cell cycle arrest, were decreased. The expression of versican was increased by niacinamide treatment in cultured hDPCs. We have found that niacinamide decreased the H2O2-induced intracellular ROS production in cultured hDPCs. Moreover, niacinamide decreased the protein expression levels of H2O2-induced p21 and p16 and diminished the secretion of H2O2-induced DKK-1. Conclusion Our data demonstrate that niacinamide could enhance hair growth by preventing oxidative stress-induced cell senescence and premature catagen entry of hair follicles.

Background Melanin is synthesized in melanocytes and transferred to keratinocytes through dendrites. Endogenous pyruvate is a key metabolite for ATP production in glycolysis, and the tricarboxylic acid (TCA) cycle and exogenous pyruvate provide protection against oxidative stress and acidosis in the intercellular space. The function of pyruvate in the regulation of dendrite outgrowth remains to be elucidated. Objective We examined the effect of pyruvate on dendritic elongation and skin pigmentation Methods Murine B16F10 melanoma cells and human primary melanocytes were used for in vitro analysis. Melanin quantitation and histochemical staining were performed in a 3D pigmented human skin model. Results We demonstrated the participation of monocarboxylate transporters (MCTs) responsible for the membrane transport of pyruvate in B16F10 melanoma cells. The accumulation of pyruvate occurred in a pH-dependent manner, which was highly sensitive to a specific MCT inhibitor (α-cyano-4-hydroxycinnamic acid). α-MSH-induced morphological changes, including dendrite elongation and growth-cone-like structure, were diminished in B16F10 cells upon treatment with pyruvate. In addition, the number of dendrite branches was reduced in normal human epidermal melanocytes. As the Rho-subfamily of monomeric GTP-binding proteins modulates dendrite formation, we subsequently examined the suppression of Rac1 activation by pyruvate, but not RhoA and Cdc42. Furthermore, pyruvate showed anti-melanogenic effects against UV-induced pigmentation in reconstructed pigmented epidermis, established by co-seeding autologous melanocytes and keratinocytes, which act similar to in vivo skin tissue. Conclusion These results suggest that pyruvate treatment may be an alternative or additive therapeutic strategy to prevent hyperpigmentation.

Facial wrinkles are the predominant phenotypes of skin aging. To date, one of the most effective ways to improve wrinkles is botulinum toxin type A (BoNT/A) injection, which inhibits muscle contractions by reducing acetylcholine release from neurons. However, since BoNT/A is a hazardous neurotoxin, the injection can only be performed by medical doctors and the procedure is only possible through invasive injection, causing inconveniences such as pain. To overcome these inconveniences, we tried to find a way to reduce wrinkles non-invasively via mechanisms similar to BoNT/A. We first designed in vitro assays to test BoNT/A-like muscle contraction inhibition in two different model systems. By using the assays, we identified Zanthoxylum piperitum (Z. piperitum) fruit extract as a BoNT-like reagent (27.7% decrease of muscle contraction rates by 1000 ppm of Z. piperitum extract treatment). Next, we determined mechanisms of how Z. piperitum extract decreases muscle contraction rates and found that the extract treatment inhibits electrical signal transduction in neurons. We also showed that among known components of Z. piperitum extract, quercitrin is responsible for muscle contraction inhibition. We further identified that Z. piperitum extract has synergistic effects with acetyl hexapeptide-8 and BoNT/A light chain, which are well-known BoNT-like peptides. Finally, we showed that topical treatment of the Z. piperitum extract indeed decreases facial wrinkles and treatment of Z. piperitum extract with acetyl hexapeptide-8 has a tendency to improve wrinkles synergistically (14.5% improvement on average). The synergistic effect of the combination is expected to improve wrinkles effectively by implementing the BoNT/A mechanisms in a non-invasive way.

Background The Janus-III measurement system evaluates the overall skin characteristics such as skin pore, wrinkle, sebum, porphyrin, skin pigmentation, and skin color using high-resolution facial images. The values are measured from five different facial areas, namely, the forehead, nose, corner of/skin below the eyes, and cheeks. Owing to its convenience and diverse measuring characteristics, Janus-III has been widely used in skin research and the cosmetic industry in Korea. In our previous study, we revealed the consistency and reliability of the system with repeatedly measured values. Its measuring performance was investigated statistically, but to make it more reliable for academic skin research, additional verification by a professional dermatologist is needed. Materials and methods In this study, we conducted comparative analysis of three skin characteristics (pigmented spot, skin color, and eye wrinkle) by a dermatologist and the Janus-III measurement system. We utilized 330 image data that were cropped from the whole facial images of 330 different participants to avoid correlation among the three measuring items. Pearson's correlation coefficient exhibited similar patterns between the system and the dermatologist's findings. Results The main finding of our study was that the measured value of skin characteristics by the Janus-III system showed clear correlation with the values evaluated by a dermatologist, especially in a pigmented spot. Conclusion Therefore, it would be a plausible idea to consider the Janus-III system for specialized research of skin characteristics even with a small sample size.

Retinol, one of the most powerful cosmetic materials for anti-aging supported by a solid scientific background, exhibits a wide range of type and severity of irritation while showing limited user compliance. The lack of understanding of the mechanism of retinol-induced irritation has been the main hurdle in the development of anti-irritation strategies. Here, we identified 30 genetic markers related to the susceptibility to retinol-induced irritation in the Korean population. Based on the genetic analysis, a novel formula against retinol-induced irritation was developed, which mitigated the molecular pathogenesis—as indicated by the genetic markers—of the retinol-induced irritation. In human tests, this formula effectively decreased retinol-induced irritation. Furthermore, a polygenic risk score model for irritation was constructed and validated. Our comprehensive approach for the analysis of retinol-induced irritation will not only aid the development of anti-irritation strategies to ensure higher user compliance but also contribute to improving the current knowledge about the biological effects of retinoids.

Dexpanthenol (D-panthenol) is a precursor of vitamin B5 (pantothenic acid) and is widely used for dietary supplements and topical applications. D-panthenol has long been used in hair care products for the purpose of anti-hair loss, its effects and the underlying mechanisms, however, were barely reported. In this study, the effects of D-panthenol on human hair follicle cells, including dermal papilla cells (hDPCs) and outer root sheath cells (hORSCs), were investigated. D-panthenol enhanced the cell viability, increasing the cellular proliferation marker Ki67 in cultured hDPCs. The markers for apoptosis (Caspase3/9) and cell senescence (p21/p16), reported to be expressed in aged or resting phase follicles, were significantly reduced by D-panthenol. Anagen-inducing factors (ALP, β-catenin, versican), which trigger or elongate the anagen phase, were stimulated by D-panthenol. On the other hand, D-panthenol reduced TGF-β1 expressions in both mRNA and protein levels. The expression of VEGF, which is important for peripheral blood vessel activation, was up-regulated by D-panthenol treatment. In cultured hORSCs, cell proliferation and viability were enhanced, while the mRNA expression of cell senescence markers (p21/p16) was significantly down-regulated. The expressions of both VEGF and its receptor (VEGFR) were up-regulated by D-panthenol. In conclusion, our data suggest that the hair growth stimulating activity of D-panthenol was exerted by increasing the cell viability, suppressing the apoptotic markers, and elongating the anagen phase in hair follicles.

Interferon-γ (IFN-γ) regulates the human immune system. To study the interaction between macrophages and natural killer (NK) cells, we established a THP-1 macrophage-conditioned media. Among the 58 natural plant extracts tested, Curcuma longa exerted the strongest IFN-γ-enhancing effect in NK-92 cells through THP-1 macrophages. C. longa extract (CLE) enhanced IFN-γ secretion 2.3- and 4.2-fold at 50 and 100 µg/ml, respectively. Therefore, we evaluated its IFN-γ-enhancing effect in vitro. Although NK-92 cells did not produce IFN-γ following treatment with C. longa, enhanced IFN-γ secretion was observed after treatment with THP-1 macrophage-conditioned media. We hypothesized that the cytokines secreted by the CLE-treated THP-1 macrophages are responsible for stimulating NK-92 cells. Cytokine array results show upregulation of cytokines, including MIP-1α, CXCL-1, IL-1β, PAI-1, and TNF-α, in CLE-treated THP-1 macrophages. To determine the cytokines responsible for augmenting IFN-γ secretion, NK-92 cells were stimulated with MIP-1α, CXCL-1, IL-1β, or PAI-1. Enzyme-linked immunosorbent assay results show that all cytokines induced IFN-γ production, although the dose response was somewhat varied. High-performance liquid chromatography analysis of CLE revealed the concentrations of three active curcuminoids, curcumin, demethoxycurcumin, and bisdemethoxycurcumin, as 6.70%, 1.00%, and 0.95%, respectively. Their mixture (with concentrations comparable to their occurrence in CLE) exerted an effect similar to that of the whole CLE. Our findings reveal that CLE indirectly stimulated NK-92 cells to secrete IFN-γ, which is mediated by cytokines produced from THP-1 macrophages. Further, we identified three curcuminoids partly responsible for this IFN-γ-enhancing effect. Therefore, C. longa can be used as a functional food ingredient owing to its immune-boosting ability. PRACTICAL APPLICATION: This study demonstrates that CLE stimulates THP-1 macrophages to secrete cytokines, which can in turn stimulate IFN-γ production by NK-92 cells. A mixture of three curcuminoids present in the extract exerted effects similar to whole CLE, demonstrating that the curcuminoids are partly responsible for the IFN-γ-enhancing effect of C. longa. Since IFN-γ is a key regulator of human immune system, these results suggest the potential use of C. longa as an immune-boosting functional food ingredient.

Adenosine is a cellular metabolite with diverse derivatives that possesses a wide range of physiological roles. We investigated the molecular mechanisms of adenosine and cordycepin for their promoting effects in wound-healing process. The mitochondrial energy metabolism and cell proliferation markers, cAMP responsive element binding protein 1 (CREB1) and Ki67, were enhanced by adenosine and cordycepin in cultured dermal fibroblasts. Adenosine and cordycepin stimulated adenosine receptor signaling via elevated cAMP. The phosphorylation of mitogen-activated protein kinase kinase (MEK) 1/2, mammalian target of rapamycin (mTOR) and glycogen synthase kinase 3 beta (Gsk3b) and Wnt target genes such as bone morphogenetic protein (BMP) 2/4 and lymphoid enhancer binding factor (Lef) 1 were activated. The enhanced gene expression by adenosine and cordycepin was abrogated by adenosine A2A and A2B receptor inhibitors, ZM241385 and PSH603, and protein kinase A (PKA) inhibitor H89, indicating the involvement of adenosine receptor A2A, A2B and PKA. As a result of Wnt/β-catenin pathway activation, the secretion of growth factors such as insulin-like growth factor (IGF)-1 and transforming growth factor beta (TGFβ) 3 was increased, previously reported to facilitate the wound healing process. In addition, in vitro fibroblast migration was also increased, demonstrating their possible roles in facilitating the wound healing process. In conclusion, our data strongly demonstrate that adenosine and cordycepin stimulate the Wnt/β-catenin signaling through the activation of adenosine receptor, possibly promoting the tissue remodeling process and suggest their therapeutic potential for treating skin wounds.

OBJECTIVE Skin-brightening agents prevent melanogenesis and reduce melanin production. However, a lower melanin content leads to weaker protection against sunlight. In this study, we evaluated the effect of lysophosphatidylcholine (LPC) and its commercial-grade product, Lysofix Dry™ (LD), on heat shock protein 70 (HSP70) expression in epidermal cells and their anti-skin photoaging effect against ultraviolet B (UVB) and blue light. METHODS The HSP70 induction was detected using ELISA. To confirm the inhibition of melanin synthesis by LPC or LD, the melanin content assay and gene expression were analyzed. Cell viability was assessed to verify whether LPC or LD prevents photo-induced skin damage. The split-face test was performed to confirm skin-brightening effect of LD. Cream formulation with 2% of LD and placebo were used for 8 weeks, and skin brightness (L) was measured with chromameter (CR-400, Konica Minolta). RESULTS LPC- and LD-induced HSP70 expression in epidermal cells. LPC and LD effectively suppressed melanogenesis provoked by α-MSH in B16 cells. They also inhibited the mRNA transcription of MITF and tyrosinase under blue light irradiation. LD increased the viability of B16 and HaCaT cells after UVB and blue light irradiation in vitro. The cream containing 2% LD increased ΔL by 1.7 after 8 weeks of use, whereas the placebo led to an increase of 0.7. CONCLUSION LPC and LD were effective in suppressing melanogenesis and enhancing cell viability under UVB and blue light via HSP70 expression. Thus, they can be considered as potent skin-brightening agents with protective effects against skin photoaging.

Background For personalized skin care, noninvasive quantitative methods to evaluate facial skin characteristics are important. Janus-III is one of the most widely used imaging analysis devices in the skin care industry in Korea. Janus-III generates values for a range of skin characteristics. Due to the convenience of obtaining results for a variety of skin characteristics in a single measurement, the use of Janus-III in cosmetic stores and research institutes has been recently increasing. However, the consistency of skin measurements of Janus-III has not been elucidated yet. Materials and methods In this study, we repeated skin measurements three times for 70 different subjects and compared each numerical value in order to assess the consistency of the Janus-III. For this purpose, we compared between-sample distances and within-sample distances. Results We found important patterns for future analyses in terms of consistency. First, the average values of skin measurement categories were more reliable than individual part values of facial segments. Second, center part values such as forehead and nose were more reliable than side part values such as left and right part segments. Conclusion If researchers who use Janus-III for studies of facial characteristics analyze average and center part values first, they can obtain relatively reliable patterns of facial skin characteristics.

This study aims to understand the mechanism of lipid loss from the hair upon contact with surfactants. We herein proposes that the process of lipid loss can be categorized into two mechanisms. In the first mechanism, the lipids inside the hair diffuse through the cell membrane complex (CMC) to the outermost layer of hair and are removed by a roll-up mechanism. In the second mechanism, the surfactant that penetrates hair directly emulsifies the lipids. The mechanism of lipid loss depends on the relative hydrophobicity of the lipid. Highly hydrophobic lipids, such as squalene and wax esters, are primarily lost through the penetration pathway, while relatively less hydrophobic lipids, such as fatty acids and cholesterol, follow the roll-up mechanism. These mechanisms were validated by confirming that surface and internal modifications of hair protected different types of lipids from the surfactant treatment.

Background Due to internal or external factors, the desquamation (turnover) rate of the stratum corneum slows down, resulting in skin problems. Therefore, adjusting the exfoliation rate through cosmetics is an important issue. Objective This report aimed to develop exfoliating agents with lesser adverse effects and higher efficiency through an ex vivo screening method and in vivo turnover rate analysis of human skin. Methods Various molecules were evaluated by the ex vivo porcine skin exfoliation method and screened for their potential as effective agents. To confirm the effect and mechanism of each agent found, the exfoliation efficiency was evaluated. Each agent was also applied to the actual human skin to determine its efficacy and side effects. Results Despite the pH 6, carnitine and serine, which have similar or better efficiency compared to PHA, were selected. Based on the results, it was confirmed that calcium. And it is nonirritating to the human skin and increases the turnover rate (~130%). Conclusion Amino acid-based exfoliating agents, such as carnitine and serine, were identified and verified to enhance the rate of exfoliation of the stratum corneum. It is expected that the improvement of dullness, mild acne, fine wrinkles, and pores through skin exfoliation in the field of cosmetics can be achieved safely through these agents.

Background The interaction between light and the skin determine how the skin looks to the human eye. Light can be absorbed, scattered, and reflected by different components of the skin in a variety of different ways. Here, we focus on the scattering properties of the outmost layer, the stratum corneum (SC). However, we currently have limited methods with which to distinguish the scattering of light by SC from the changes due to other components of the skin. Materials and methods Dark-field images of tape-striped corneocytes were used in vitro to study the differences in light scattered by the SC and other skin components. Several optical clearing agents (OCAs) were tested for their ability to reduce light scattering. Physical properties of the SC (water content, keratin configuration, and volume) after OCA treatment were investigated using FT-IR, confocal Raman microscopy, and 3D laser microscopy. Results Urea derivatives, several reducing sugars, and sugar alcohols, which were used as OCA in optics and also used as humectants in cosmetic area, could reduce scattering. However, unlike dehydration in optics, penetration of water into the keratin was increased at low OCA concentrations. In such conditions, the volume of corneocytes was increased but their stiffness was reduced. Conclusion By analyzing the tape-striped SC, we were able to measure the changes in the optical and physical properties of corneocytes in response to OCAs. Hydration of the SC layer by OCAs reduces light scattering from the corneocytes and would be helpful in moisturizing the skin and helping the skin look healthy.

Glyceryl monooleate (GMO) is a polar lipid that can exist in various liquid crystalline phases in the presence of different amounts of water. It is regarded as a permeation enhancer due to its amphiphilic property. Various phases of GMO/solvent system containing sodium fluorescein were prepared to compare permeability using confocal laser scanning microscopy (CLSM). GMO was melted in a vial in a water bath heated to 45 °C. Propylene glycol and hexanediol were homogeneously dissolved in the melted GMO. Sodium fluorescein in aqueous solution was diluted to various ratios and thoroughly mixed by an ultrasonic homogenizer. Each GMO/Solvent system with fluorescein was applied onto the epidermal side of excised pig skin and incubated overnight. CLSM was performed to observe how the GMO/solvent system in its different phases affect skin permeability. Cubic and lamellar phase formulations enhanced the fluorescein permeation through the stratum corneum. A solution system had the weakest permeability compared to the other two phases. Due to the amphiphilic nature of GMO, cubic and lamellar phases might reduce the barrier function of stratum corneum which was observed by CLSM as fluorescein accumulated in the dermis. Based on the results, the glyceryl monooleate lyotropic mixtures could be applied to enhance skin permeation in various topical and transdermal formulations.

A hollow microneedle (HM) was prepared to deliver a phenylephrine (PE) solution into the anal sphincter muscle as a method for treating fecal incontinence. The goal of this study was the local targeted delivery of PE into the sphincter muscle through the perianal skin with minimal pain using hollow microneedles, resulting in the increase of resting anal sphincter pressure. PE was administered on the left and the right sides of the anus of a rat through the perianal skin using 1.5mm long HM. An in vivo imaging system study was conducted after injection of Rhodamine B, and a histological study was performed after injection of gentian violet. The resting anal sphincter pressure in response to various drug doses was measured by using an air-charged catheter. Anal pressure change produced by HM administration was compared with change produced by intravenous injection (IV), subcutaneous (SC) injection and intramuscular (IM) injection. The change in mean blood pressure produced by HM administration as a function of PE dose was compared with change produced by PBS injection. A pharmacokinetic study of the new HM administration method was performed. A model drug solution was localized in the muscle layer under the perianal skin at the injection site and then diffused out over time. HM administration of PE induced significant contraction of internal anal sphincter pressure over 12h after injection, and the maximum anal pressure was obtained between 5 and 6h. Compared to IV, SC and IM treatments, HM treatment produced greater anal pressure. There was no increase in blood pressure after HM administration of PE within the range of predetermined concentration. Administration of 800μg/kg of PE using HM produced 0.81±0.38h of tmax. Our study suggests that HM administration enables local delivery of a therapeutic dose of PE to the anal sphincter muscle layer with less pain. This new treatment has great potential as a clinical application because of the ease of the procedure, minimal pain, and dose-dependent response.

A breakthrough in the efficient transdermal delivery of drug via the laser-driven microjet is reported. A single source of laser beam is split into two: one beam ablates a targeted spot on a skin and another beam drives the injector for fast microjet ejection into a preablated spot. This combined ablation and microjet injection scheme using a beam splitter utilizes laser energy sharing between generation of the microhole via ablation and the microjet which is generated using the Er:YAG laser beam at a 2940-nm wavelength and pulse duration. A careful analysis of the injection mechanism is carried out by studying the response of the elastic membrane that separates a driving water unit for bubble expansion from a drug unit for a microjet ejection. The efficiency of the present delivery scheme is evaluated by the abdominal porcine skin test using the fluorescein isothiocyanate staining and the confocal microscopy for quantitative delivery confirmation. The depth of penetration and the injected volume of the drug are also confirmed by polyacrylamide gel tests.

It was demonstrated that the trans-activating transcriptional activator (TAT) protein from HIV-1 could enter cells when added to the surrounding media. TAT peptide chemically attached to various proteins was able to deliver these proteins to various cells and even at high levels in heart and spleen tissues in mice. In this study, the tri-peptide GKH (glycine–lysine–histidine) derived from the parathyroid hormone, which is known as a lipolytic peptide, was attached to 9-poly lysine (TAT) to be used as a cosmetic ingredient for eye-bag care product. When glycerol is released, expressed as the extracellular glycerol concentration (the so-called lipolysis index), TAT–GKH at 10−5m induces a maximal lipolytic effect of approximately 41.5% in epididymal adipocytes isolated from rats, compared with basal lipolysis. In a microdialysis study, TAT–GKH was perfused into epididymal adipose tissues of anaesthetized rats in increasing concentrations in a Ringer solution. The glycerol concentration in each dialysate was measured using an ultra-sensitive radiometric method. The perfusion of TAT–GKH induced a lipolytic effect. A penetration study showed that TAT–GKH resulted in a sevenfold higher penetration into excised hairless mice skin than GKH. An in vivo study showed that a TAT–GKH containing emulsion had a better effect upon the relative volume reduction of eye bag after 28 days of application on 22 healthy female volunteers than the placebo. It was therefore concluded that TAT–GKH increased skin penetration, which resulted in enhanced lipolytic effects in in vitro, ex vivo and in volume reduction of eye-bags in in vivo studies.