Biostimulatory effects of polydioxanone, poly-d, l lactic acid, and polycaprolactone fillers in mouse model.

BACKGROUND: Numerous fillers are increasingly used for augmentation of volume loss and relaxation of facial wrinkles. Collagen stimulators are the latest next-generation dermal fillers that can induce neocollagenesis. To investigate biophysical characteristics, safety, and efficacy of newly developed polydioxanone (PDO) filler in comparison with poly-l lactic acid (PLLA) and polycaprolactone (PCL) fillers. METHODS: In vitro assay, morphology of particles, and rheological property of fillers were measured. A total of 24 female hairless mice (SKH1-Hrhr ) were randomly divided into three groups and injected with PDO, PLLA, or PCL fillers. Durability of fillers was assessed at 0, 3 days, and 1, 4, 8, 12 weeks after injection using folliscope and PRIMOS. To determine biocompatibility and neocollagenesis, histologic evaluation was performed at 1, 4, 8, and 12 weeks after injection. Efficacy was also evaluated based on skin surface roughness changes using PRIMOS in a hairless mouse photoaging model. RESULTS: In the particle morphology test, PDO microspheres had an irregular surface and were spherical and uniformly sized. PDO filler demonstrated similar neocollagenesis and inflammatory response to other collagen stimulators. PDO filler showed better biodegradability than PLLA and PCL fillers. In the hairless mouse photoaging model, there was a statistically significant decrease in skin surface roughness after PDO filler injection. CONCLUSIONS: Our data suggest that newly developed collagen stimulating PDO filler might be a safe and effective option for correction of volume loss and rejuvenation of photoaging skin.

Therapeutic potential of topically administered γ-AlOOH on 2,4-dinitrochlorobenzene-induced atopic dermatitis-like lesions in Balb/c mice.

Boehmite (γ-AlOOH) has a wide range of applications in a variety of industrial and biological fields. However, little is known about its potential roles in skin diseases. The current study investigated its effect on atopic dermatitis (AD). Following characterization, cytotoxicity, pro-inflammatory response and oxidative stress associated with boehmite were assessed, using TNF-α-induced keratinocytes and mast cells. In addition, therapeutic effects of boehmite, topically administered to Balb/c mice induced by 2,4-dinitrochlorobenzene (DNCB), were evaluated. Expression of cytokines (TLSP, IL-25 and IL-33) and the generation of ROS from keratinocytes induced by TNF-α were significantly inhibited by boehmite without affecting cell viability. MAPKs (ERK, JNK and p38) required for cytokine expression were suppressed by boehmite treatment. Up-regulation of cytokines (TSLP, IL-4, IL-5, IL-13, RANTES) in human mast cells treated with phorbol 12-myristate 13-acetate and calcium ionophore was also suppressed by boehmite. Boehmite improved the AD severity score, epidermal hyperplasia and transepidermal water loss in DNCB-induced AD-like lesions. Moreover, Th2-mediated cytokine expression, mast cell hyperplasia and destruction of the skin barrier were improved by boehmite treatment. Overall, we demonstrated that boehmite may potentially protect against AD.