Utilization of ex vivo tissue model to study skin regeneration following microneedle stimuli.

Microneedling is a popular skin resurfacing and rejuvenation procedure. In order to develop better adjunct products for consumers, there is a scientific need to establish greater understanding of the mechanism in which microneedling stimulates regeneration within skin. The purpose of this study is to develop a physiologically relevant ex vivo tissue model which closely mimics the actual microneedling procedure to elucidate its mechanism of action. In this study, human ex vivo skin was subjected to microneedling treatment and cultured for 6 days. Histological analysis demonstrated that the ex vivo skin was able to heal from microneedling injury throughout the culture period. Microneedling treatment stimulated proliferation and barrier renewal of the skin. The procedure also increased the levels of inflammatory cytokines and angiogenic growth factors in a dynamic and time dependent fashion. The tissue demonstrated hallmark signs of epidermal regeneration through morphological and molecular changes after the treatment. This is one of the first works to date that utilizes microneedled ex vivo skin to demonstrate its regenerative behavior. Our model recapitulates the main features of the microneedling treatment and enables the evaluation of future cosmetic active ingredients used in conjunction with microneedling.

Characterization of a New Reconstructed Full Thickness Skin Model, T-Skin™, and its Application for Investigations of Anti-Aging Compounds.

BACKGROUND: We have characterized a new reconstructed full-thickness skin model, T-Skin™, compared to normal human skin (NHS) and evaluated its use in testing anti-aging compounds. METHODS: The structure and layer-specific markers were compared with NHS using histological and immunohistological staining. In anti-aging experiments, T-SkinTM was exposed to retinol (10 µM) or vitamin C (200 µM) for 5 days, followed by immunohistological staining evaluation. RESULTS: T-Skin™ exhibits a well stratified, differentiated and self-renewing epidermis with a dermal compartment of functional fibroblasts. Epidermal (cytokeratin 10, transglutaminase 1), dermo-epidermal junction (DEJ) (laminin 5, collagen-IV, collagen VII) and dermally-located (fibrillin 1, procollagen I) biomarkers were similar to those in NHS. Treatment of T-Skin™ with retinol decreased the expression of differentiation markers, cytokeratin 10 and transglutaminase 1 and increased the proliferation marker, Ki67, in epidermis basal-layer cells. Vitamin C increased the expression of DEJ components, collagen IV and VII and dermal procollagen 1. CONCLUSIONS: T-Skin™ exhibits structural and biomarker location characteristics similar to NHS. Responses of T-Skin™ to retinol and vitamin C treatment were consistent with those of their known anti-aging effects. T-Skin™ is a promising model to investigate responses of epidermal, DEJ and dermal regions to new skin anti-ageing compounds.

Tissue-engineered ligament: implant constructs for tooth replacement.

AIM: A tissue-engineered periodontal ligament (PDL) around implants would represent an important new therapeutic tool to replace lost teeth. The PDL is the key to tooth anchoring; it connects tooth root and alveolar bone, and it sustains bone formation. MATERIALS AND METHODS: Cells were isolated from PDL and cultured in a bioreactor on titanium pins. After the formation of multiple cellular layers, pins were implanted in enlarged dental alveolae. MAIN OUTCOME MEASURES: Cell-covered implants integrated without adverse effects, and induced bone in their vicinity. RESULTS: A histological examination of a dog model revealed that cells were arranged in a typical ligament-like fashion. In human patients, product safety was ascertained for 6-60 months. Probing and motility assessments suggested that the implants were well integrated with mechanical properties similar to those of teeth. Radiographs demonstrated the regeneration of deficient alveolar bone, the development of a lamina dura adjacent to a mineral-devoid space around the implant and implant migration in an intact bone structure. CONCLUSIONS: New tissue consistent with PDL developed on the surface of dental implants after implantation. This proof-of-principal investigation demonstrates the application of ligament-anchored implants, which have potential advantages over osseointegrated oral implants.