Hélène Tauzin

Development and characterization of a human dermal equivalent with physiological mechanical properties.

Different models of reconstructed skin are available, either to provide skin wound healing when this process is deficient, or to be used as an in vitro model. Nevertheless, few studies have focused on the mechanical properties of skin equivalent. Indeed, human skin is naturally under tension. Taking into account these features, the purpose of this work was to obtain a cellularized dermal equivalent (CDE), composed of collagen and dermal fibroblasts.

Mécano-Stimulation™ of the skin improves sagging score and induces beneficial functional modification of the fibroblasts: clinical, biological, and histological evaluations

Background Loss of mechanical tension appears to be the major factor underlying decreased collagen synthesis in aged skin. Numerous in vitro studies have shown the impact of mechanical forces on fibroblasts through mechanotransduction, which consists of the conversion of mechanical signals to biochemical responses. Such responses are characterized by the modulation of gene expression coding not only for extracellular matrix components (collagens, elastin, etc.) but also for degradation enzymes (matrix metalloproteinases [MMPs]) and their inhibitors (tissue inhibitors of metalloproteinases [TIMPs]). A new device providing a mechanical stimulation of the cutaneous and subcutaneous tissue has been used in a simple, blinded, controlled, and randomized study. Materials and methods Thirty subjects (aged between 35 years and 50 years), with clinical signs of skin sagging, were randomly assigned to have a treatment on hemiface. After a total of 24 sessions with Mécano-Stimulation™, biopsies were performed on the treated side and control area for in vitro analysis (dosage of hyaluronic acid, elastin, type I collagen, MMP9; equivalent dermis retraction; GlaSbox®; n=10) and electron microscopy (n=10). Furthermore, before and after the treatment, clinical evaluations and self-assessment questionnaire were done. Results In vitro analysis showed increases in hyaluronic acid, elastin, type I collagen, and MMP9 content along with an improvement of the migratory capacity of the fibroblasts on the treated side. Electron microscopy evaluations showed a clear dermal remodeling in relation with the activation of fibroblast activity. A significant improvement of different clinical signs associated with skin aging and the satisfaction of the subjects were observed, correlated with an improvement of the sagging cheek. Conclusion Mécano-Stimulation is a noninvasive and safe technique delivered by flaps microbeats at various frequencies, which can significantly improve the skin trophicity. Results observed with objective measurements, ie, in vitro assessments and electron microscopy, confirm the firming and restructuring effect clinically observed.

A human skin culture system for a wound-healing model.

The human body is very vulnerable and has to deal with open wounds due to injuries or diseases. A human skin culture model could help us to investigate wound-healing processes in an effort to find ...

Evaluation of lifting and antiwrinkle effects of calcium hydroxylapatite filler. In vitro quantification of contractile forces of human wrinkle and normal aged fibroblasts treated with calcium hydroxylapatite

As it ages, the skin changes, it loses its natural hydration and its fundamental substance degenerates. Due to a lack of hydration and nutrients, collagen production decreases. This support tissue of the skin weakens, losing tone and firmness. Depressions form on the skins surface: these are wrinkles. Wrinkles are one of the first visible signs of the skins aging, and mainly occur on the face.