Quantitative evaluation of facial sagging in different body postures using a three-dimensional imaging technique.

BACKGROUND: The possible contribution of head flexion posture while using a smartphone to the formation of "smartphone face," is an increasing concern. Smartphone face describes the facial changes in a stooped posture receiving more gravitational pull on the jowl area. AIMS: In this study, we quantified facial sagging in different postural changes using a three-dimensional imaging technique. METHODS: Faces of 21 young (30.45 ± 2.81 yo, n = 11) and old (59.50 ± 3.37 yo, n = 10) Korean female subjects were scanned in different body postures including standing, supine, and head flexion (30°, 45°). The landmark displacements and volumetric changes in facial areas were assessed and correlated with skin elasticity. In addition, 22 Korean female subjects (45.45 ± 3.81 yo) were recruited to test the anti-gravity effect of facial cream A, which was formulated with Stem III complex™, for 8 weeks. RESULTS: The landmarks shifted inferior-laterally with the supine posture, while the upper face shifted more laterally and the lower face shifted more inferiorly. With a head flexion posture, facial sagging occurred mainly toward the anterior direction with more prominent changes in the lower face. The changes were greater in the older group, and skin elasticity exhibited negative correlation with the shifting distances. A significant decrease in facial sagging was noted after an 8-week treatment of facial cream A. CONCLUSION: The use of a three-dimensional imaging technique could accurately assess the gravity-induced facial changes in different postures. The head flexion posture particularly gives more gravitational pull to the lower face, which could contribute to the drooping jawline.

Physical properties of a novel small-particle hyaluronic acid filler: In vitro, in vivo, and clinical studies.

BACKGROUND: Infraorbital region is one of the most important regions that show the signs of aging. In recent years, hyaluronic acid (HA) fillers have been used to correct this region for esthetic treatments. Although HA fillers with various physical properties are used, limited research has been performed to compare their efficacy. OBJECTIVE: We aimed to compare three HA fillers to determine which is the most appropriate filler for the correction of the infraorbital region and evaluate the correction of such by performing a clinical test using CLEVIEL Fine. METHODS: We performed in vitro and in vivo tests using one new HA filler and two other commercial HA fillers. We compared the rheological properties, resistance to degradation, and in vivo duration test results of the three fillers. Nine patients participated in the clinical test using CLEVIEL Fine for 24 weeks. RESULTS: CLEVIEL Fine showed good rheological and physical characteristics for the infraorbital region. It had a low elasticity and cohesiveness, low incidence of postinjection swelling, high tanδ, narrow particle distribution, and small particle size. Further, it showed better resistance to the enzymes and radicals in the in vitro test than the other two HA fillers and a similar duration in the mouse test. In the clinical test, all patients showed good elasticity and hydration in the infraorbital region for 24 weeks. CONCLUSIONS: CLEVIEL Fine was proven to be safe and effective based on the in vitro, in vivo, and clinical study results.

De novo tyrosinase inhibitor: 4-(6,7-dihydro-5H-indeno[5,6-d]thiazol-2-yl)benzene-1,3-diol (MHY1556).

In this study, we have synthesized and studied de novo tyrosinase inhibitor, MHY1556, which showed significantly better efficacy than other pre-existing tyrosinase inhibitors in vitro experiments. The IC50 value of MHY1556 was 0.50µM which was significantly lower than that of kojic acid (IC50=53.95µM), which is a well-known tyrosinase inhibitor and was used as a positive control in this study. We predicted the tertiary structure of tyrosinase, simulated the docking with compound MHY1556 and confirmed that the compound strongly interacts with mushroom tyrosinase residues. Substitutions with a hydroxy group at both R1 and R3 of the phenyl ring indicated that these groups play a major role in the high binding affinity to tyrosinase, especially through the hydrogen bonding interaction of the hydroxyl group at R1 with GLY281. In addition, MHY1556 showed concentration-dependent inhibitory effects in melanin content assay where B16F10 melanoma cells were treated with α-melanocyte stimulating hormone (α-MSH), and also there is no significant cytotoxicity of this compound in cell viability assay conducted in B16F10 melanoma cells. The tyrosinase activity assay results with MHY1556 also support its potent inhibitory effects. Therefore, our data strongly suggest MHY1556 suppresses the melanogenesis via a tyrosinase inhibitory effect.

Suppression of melanogenesis by a newly synthesized compound, MHY966 via the nitric oxide/protein kinase G signaling pathway in murine skin.

BACKGROUND: Ultraviolet B (UVB) radiation is the main physiological stimulus for skin pigmentation. Nitric oxide (NO) and the NO/PKG signaling pathway play an important role in UVB-induced melanogenesis, which is related to the induction of expression of tyrosinase. In an attempt to find a novel anti-melanogenic agent, we synthesized a new compound, 2-bromo-4-(5-chloro-benzo[d]thiazol-2-yl) phenol (MHY966). OBJECTIVE: The purpose of this study was to investigate the action of MHY966 on NO and the NO-mediated signaling pathway using in vitro and in vivo models of melanogenesis. METHODS: NO generation, melanin synthesis, and the expression of tyrosinase and PKG were measured in B16F10 melanoma cells to verify the anti-melanogenic effect of MHY966 in vitro. Next, melanin-possessing hairless mice were pre-treated with MHY966 and then irradiated with UVB repeatedly. Morphological, histological, and biochemical analyses including the expressions of PKG, tryosinase and nuclear MITF, and productions of nitric oxide, peroxynitrite and ROS were conducted. RESULTS: MHY966 effectively inhibited NO generation and subsequent melanin synthesis induced by sodium nitroprusside, an NO donor, and suppressed the expression of tyrosinase and PKG. Topical application of MHY966 dose-dependently attenuated UVB-induced pigmentation in a mouse model. This hypopigmentation effect induced by MHY966 treatment was mediated by the down-regulation of tyrosinase, PKG, and nuclear MITF, which was accompanied by decreased NO and NO-related oxidative stress. CONCLUSION: The novel compound, MHY966 had an inhibitory effect on NO generation and the NO-mediated signaling pathway leading to the down-regulation of tyrosinase. The significance of the present study is the finding of a promising anti-melanogenic agent targeting the NO/PKG signaling pathway.