Eun Ja Choi

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.

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.

Targeting of sebaceous glands to treat acne by micro-insulated needles with radio frequency in a rabbit ear model

Many studies have investigated the application of micro‐insulated needles with radio frequency (RF) to treat acne in humans; however, the use of a micro‐insulated needle RF applicator has not yet been studied in an animal model. The purpose of this study was to evaluate the effectiveness of a micro‐insulated needle RF applicator in a rabbit ear acne (REA) model.

Effect of a 308‐nm excimer laser on atopic dermatitis‐like skin lesions in NC/Nga mice

Atopic dermatitis (AD) is a common inflammatory skin disease that can affect all age groups. It has a relapsing course, which dramatically affects the quality of life of patients. A 308‐nm excimer laser has been reported to be a safe and effective treatment for inflammatory skin diseases, although the range of potential application has not been fully explored. The purpose of this study was to evaluate the therapeutic effects of a 308‐nm laser on AD‐like skin lesions in NC/Nga mice.

Gain-switched 311-nm Ti:Sapphire laser might be a potential treatment modality for atopic dermatitis

Phototherapy with 311-nm narrowband-UVB (NBUVB) is an effective adjuvant treatment modality for atopic dermatitis (AD). In this study, we evaluated the therapeutic effect of the newly developed gain-switched 311-nm Ti:Sapphire laser device using a NC/Nga mouse AD model. A total number of 50 mice were used in this study. Atopic dermatitis (AD) was induced in mice by exposure to Dermatophagoides farina. These, NC/Nga mice were then treated with conventional 311-nm NBUVB or the newly developed gain-switched 311-nm Ti:Sapphire laser. The clinical features, dermatitis severity scores, and scratching behavior were assessed. In addition, serologic analyses including inflammatory cytokines and histological analyses were performed. Gain-switched 311-nm Ti:Sapphire laser improved the AD-like skin lesions, severity, and symptoms of AD in the NC/Nga mouse model. This new laser also modulated the immune response found in the AD model, including hyper-IgE, upregulated Th2 cytokines, and the Th2-mediated allergic inflammatory reaction. Gain-switched 311-nm Ti:Sapphire laser shows therapeutic promise via an immune-modulation mechanism in an AD mouse model. These data suggest that gain-switched 311-nm Ti:Sapphire laser may be useful as a targeted phototherapy modality for AD.

Ultraviolet light-emitting-diode irradiation inhibits TNF-α and IFN-γ-induced expression of ICAM-1 and STAT1 phosphorylation in human keratinocytes.

Ultraviolet light‐emitting diodes (UV‐LEDs) are a novel light source for phototherapy. This research investigated the in vitro safety and efficacy of UV‐LEDs as a phototherapeutic device for atopic dermatitis (AD).

The efficacy and safety of a monophasic hyaluronic acid filler in the correction of nasolabial folds: A randomized, multicenter, single blinded, split‐face study

The different rheological properties of hyaluronic acid (HA) filler reflect their specific manufacturing processes and resultant physicochemical characteristics. However, there are few researches about the relationship between product differences and clinical outcome when HA fillers are used for nasolabial folds (NLFs).

Inhibitory effect of 660‐nm LED on melanin synthesis in in vitro and in vivo

Skin hyperpigmentary disorders including postinflammatory hyperpigmentation, melasma, solar lentigines, and conditions like freckles are common. The light‐emitting diodes (LEDs) are the latest category of nonthermal and noninvasive phototherapy to be considered in skin pigmentation disorder treatment.

Three-Dimensional Imaging as a Novel Method of Evaluating the Longevity of Hyaluronic Acid Fillers in a Mouse Model

Hyaluronic acid (HA) is a biocompatible material that can be removed by enzyme (hyaluronidase) degradation and reabsorbed over a period of 6 to 12 months. Therefore, injection of HA filler for facial volume augmentation should be repeated every few months. Thus, physicians and manufacturers are actively seeking newHA fillers with longer-lasting efficacy. To ensure this longevity, resistance to degradation and preservation of the 3-dimensional (3D) shape are required.