Chang Taek Oh

Investigating skin penetration depth and shape following needle-free injection at different pressures: A cadaveric study

The effectiveness of needle‐free injection devices in neocollagenesis for treating extended skin planes is an area of active research. It is anticipated that needle‐free injection systems will not only be used to inject vaccines or insulin, but will also greatly aid skin rejuvenation when used to inject aesthetic materials such as hyaluronic acid, botulinum toxin, and placental extracts. There has not been any specific research to date examining how materials penetrate the skin when a needle‐free injection device is used. In this study, we investigated how material infiltrates the skin when it is injected into a cadaver using a needle‐free device.

Superoxide Dismutase 1 Inhibits Alpha-Melanocyte Stimulating Hormone and Ultraviolet B-Induced Melanogenesis in Murine Skin

Background Over the last decade, the incidence of ultraviolet B (UVB)-related skin problems has increased. Oxidative stress caused by UVB induces the secretion of melanocyte growth and activating factors from keratinocytes, which results in the formation of cutaneous hyperpigmentation. Therefore, increasing the antioxidant abilities of skin cells is thought to be a beneficial strategy for the development of sunscreen agents. Superoxide dismutase 1 (SOD1) is an antioxidant enzyme that is known to exhibit antioxidant properties. Objective The purpose of this study was to investigate the effect of SOD1 on alpha-melanocyte stimulating hormone (α-MSH) and UVB-induced melanogenesis in B16F10 melanoma cells and HRM-2 melanin-possessing hairless mice. Methods The inhibitory effect of SOD1 on tyrosinase activity was evaluated in a cell-free system. Additional experiments were performed using B16F10 melanoma cells to demonstrate the effects of SOD1 in vitro, and HRM-2 melanin-possessing hairless mice were used to evaluate the antimelanogenic effects of SOD1 in vivo. Results We found that SOD1 inhibited melanin production in a dose-dependent manner without causing cytotoxicity in B16F10 melanoma cells. SOD1 did not inhibit tyrosinase activity under cell-free conditions. The results indicate that SOD1 may reduce pigmentation by an indirect, nonenzymatic mechanism. We also found that SOD1 decreased UVB-induced melanogenesis in HRM-2 melanin-possessing hairless mice, as visualized through hematoxylin and eosin staining and Fontana-Masson staining. Conclusion Our results indicate that SOD1 has an inhibitory effect on α-MSH and UVB-induced melanogenesis, indicating that SOD1 may be a promising sunscreen agent.

Improved methods for selective cryolipolysis results in subcutaneous fat layer reduction in a porcine model.

Cryolipolysis is a noninvasive method for the selective reduction of localized fat tissues. It has demonstrated efficacy in both clinical and preclinical trials; however, despite its popularity, its mechanisms of action and evaluation methods are not yet fully defined. The purpose of this study was to improved methods for cryolipolysis using a porcine model.

Therapeutic Effects of Full Spectrum Light on the Development of Atopic Dermatitis-like Lesions in NC/Nga Mice

Full spectrum light (FSL) includes UVA, visible light and infrared light. Many studies have investigated the application of FSL in severe cases of atopic dermatitis (AD) in humans; however, FSL has not yet been studied in an animal model. The purpose of this study was to evaluate the therapeutic effects of FSL on AD‐like skin lesions using NC/Nga mice, with the aim of mitigating itching and attenuating the expression of adhesion molecules. We examined the effects of FSL on mite allergen‐treated NC/Nga mice by assessing skin symptom severity, ear thickness, serum IgE levels, and the cytokine expression. We examined the histology of lesions using hematoxylin–eosin, toluidine blue and immunohistochemical staining. Our findings suggest that FSL phototherapy exerts positive therapeutic effects on Dermatophagoides farinae (Df)‐induced AD‐like skin lesions in NC/Nga mice by reducing IgE levels, thus promoting recovery of the skin barrier. The mechanisms by which FSL phototherapy exerts its effects may also involve the inhibition of scratching behavior, reduction of IL‐6 levels and reductions in adhesion molecule expression. The present study indicates that FSL phototherapy inhibits the development of AD in NC/Nga mice by suppressing cytokine, chemokine and adhesion molecule expression, and thus, could potentially be useful in treating AD.

Transcutaneous pneumatic injection of glucose solution: a morphometric evaluation of in vivo micropig skin and tissue-mimicking phantom.

Needle‐free, transcutaneous pneumatic injection systems can be used to deliver therapeutic solutions to targeted layers of skin in a minimally invasive manner.

A novel adamantyl benzylbenzamide derivative, AP736, inhibits melanogenesis in B16F10 mouse melanoma cells via glycogen synthase kinase 3β phosphorylation

Recently, much effort has been made to develop effective dermatological depigmenting compounds. In this study, we investigated the novel candidate compound, AP736 (an adamantyl benzylbenzamide derivative), and its effects on melanogenesis in B16F10 melanoma cells, as well as the mechanisms involved. AP736 has been reported to exert anti-melanogenic effects in melanocytes in vitro and in artificial skin equivalents through the inhibition of key melanogenic enzymes and the suppression of the cAMP-protein kinase A (PKA)-cAMP response element‑binding protein (CREB) signaling pathway. Thus, we examined another pathway of melanogenesis involving the effects of AP736 on the glycogen synthesis kinase 3β (GSK3β) pathway. Melanin content and tyrosinase activity were measured using a spectrophotometer after the cells were treated with AP736. The AP736-induced activation of signaling pathways was examined by western blot analysis. We confirmed that AP736 decreased melanin production in a dose-dependent manner; however, it did not directly inhibit tyrosinase, the rate-limiting melanogenic enzyme. The expression of microphthalmia-associated transcription factor, tyrosinase, and related signal transduction pathways was also investigated. The Wnt signaling pathway is deeply involved in melanogenesis; therefore, phosphorylation by GSK3β was assessed following treatment with AP736. AP736 induced GSK3β phosphorylation (inactivation), but it did not alter the level of β-catenin. Furthermore, the expression of α-melanocyte-stimulating hormone-induced tyrosinase was downregulated by AP736. Our data suggest that AP736 exerts hypopigmentary effects through the downregulation of tyrosinase via GSK3β phosphorylation.

Potential synergistic effects of human placental extract and minoxidil on hair growth‐promoting activity in C57BL/6J mice

Human placenta extract (HPE) has been used to alleviate tiredness and promote wound healing, and for its antiageing functions; however, it has not yet been studied for its effects on hair growth. In the present study, we evaluated the in vitro effect of HPE on hair growth by observing its actions on human dermal papilla cells (DPCs).

Conditioned medium from human bone marrow-derived mesenchymal stem cells promotes skin moisturization and effacement of wrinkles in UVB-irradiated SKH-1 hairless mice.

Mesenchymal stem cells (MSCs) are promising therapeutic agents for various diseases.

Needle-free jet injection of hyaluronic acid improves skin remodeling in a mouse model

PURPOSE The purpose of this study was to improve methods of jet injection using a mouse model. We investigated the mechanism of action, efficacy, and safety of the pneumatic device using injection of hyaluronic acid (HA) solution into a mouse model. METHODS We evaluated the efficacy and safety of an INNOJECTOR™ pneumatic device that pneumatically accelerates a jet of HA solution under high pressure into the dermis of mouse skin. We examined the treatment effects using skin hybrid model jet dispersion experiments, photographic images, microscopy, and histological analyses. RESULTS Use of the INNOJECTOR™ successfully increased dermal thickness and collagen synthesis in our mouse model. Jet dispersion experiments were performed using agarose gels and a polyacrylamide gel model to understand the dependence of jet penetration on jet power. The mechanisms by which pneumatic injection using HA solution exerts its effects may involve increased dermal thickening, triggering of a wound healing process, and activation of vimentin and collagen synthesis. CONCLUSIONS Collagen synthesis and increased dermal thickening were successfully achieved in our mouse model using the INNOJECTOR™. Pneumatic injection of HA under high pressure provides a safe and effective method for improving the appearance of mouse skin. Our findings indicate that use of the INNOJECTOR™ may induce efficient collagen remodeling with subsequent marked dermal layer thickening by targeting vimentin.

Inhibitory effects of Stichopus japonicus extract on melanogenesis of mouse cells via ERK phosphorylation

Stichopus japonicus has been used as a folk medicine and as an ingredient in traditional food in East Asian countries. In recent years, the bioactive compounds found in S. japonicus have been reported to possess efficacy in wound healing and may be of potential use in the cosmeceutical, pharmaceutical and biomedical industries. Although the components and their functions require further investigation, S. japonicus extracts exhibit anti-inflammatory properties, and may be used for cancer prevention and treatment. Although several reports have examined different aspects of S. japonicus, the effects of S. japonicus extract on melanogenesis in the skin has not been reported to date. Therefore the present study aimed to investigate the effects of S. japonicus extract on melanogenesis. Treatment with a mixture of S. japonicus extracts (MSCE) reduced melanin synthesis and tyrosinase (TYR) activity in mouse melanocyte cells lines, B16F10 and Melan-A. In addition, MSCE treatment reduced the protein expression levels of TYR, tyrosinase-related protein-1 and tyrosinase-related protein-2. The reduced protein levels may be the result of decreased microphthalmia-associated transcription factor (MITF) expression, which is an important regulator of melanogenesis. The reduced expression level of MITF was associated with delayed phosphorylation of extracellular signal-regulated kinase (ERK) induced by MSCE treatment. A specific MEK inhibitor, PD98059, significantly blocked MSCE-mediated inhibition of melanin synthesis. In conclusion, these results indicate that MSCE may be useful as a potential skin-whitening compound in the skin medical industry.