AccuSkin

Technology

BioEngineered AccuSkin™

Xgene’s cell-sorted organ regeneration technology provides a new, accurate method to re-create many human tissue-specific 3-D models of epithelial-mesenchyme composition. Our current effort has been focused on providing full-thickness skin equivalents and bi-layered corneal equivalents, called AccuSkin™ and AccuCornea™, respectively. The current norm is to replace the traditional animal tests, e.g., Draize test with in vitro organotypic assays in order to comply with new regulatory requirements, such as the EEC ban on animal testing (European Economic Community) that will take effect in January-2009. Consumer products, cosmetic and pharmaceutical companies worldwide are actively seeking suitable alternative methods for long-used routine animal tests to comply with these new regulations before they go into effect.

Comparison of human skin and AccuSkin

Xgene scientists first observed that uniformly mixed keratinocytes and fibroblasts when placed inside an inert chamber on the back of SCID mice resulted in a full-thickness skin. Using the same combination of primary keratinocytes and fibroblasts, we have successfully translated this in vivo observation into making human skin equivalents in vitro, termed AccuSkin™, using Xgene's Cell-Sorted Skin Equivalent (CeSSE) technology (right panel). Since CeSSE technology does not utilize any exogenous collagen or cadaver derived matrix to reconstruct the dermal scaffold, it allows for more physiologically relevant measurements of changes to the dermal matrix in AccuSkin samples as compared to those prepared by the collagen-gel method. Shown below are H&E stained sections of human skin (left) and AccuSkin™ (right).

Human Skin AccuSkin™ (in vitro)

AccuSkin Manufacturing Schematics

Skin Products and Services

Standard Skin Products

Our standard premiere product AccuSkin is a “full-thickness” bi-layer skin assay system composed of the epidermal and dermal layers. In contrast to competitors' composite or epidermal-only models for routine testing, AccuSkin has established an important niche in the marketplace by providing a human skin model capable of cross-talk because this is the only product not using exogenous matrix nor scaffold to encapsulate the fibroblasts, so any physiological cellular interactions generated between the cell types are closer to the natural skin than those of the composite models. AccuSkin system has advantages over composite models, for example, in cosmetic drug efficacy assessment within the dermis, especially in assessing modulation of synthesis vs. degradation of structural matrix protein(s) and/or proteoglycan(s).

Standard AccuSkin™ plate is currently offered in 96-well formats with 32 wells per plate using normal human primary keratinocytes and fibroblasts as the input cells. Complimentary maintenance medium and instruction sheet will be provided in each AccuSkin shipment.

Custom Skin Services

Custom-tailored AccuSkin™ can be reconstructed with a wide choice of skin cell characteristics. For example, the input cell types can be derived from young vs. old donors, normal vs. disease-afflicted skin biopsies, and/or genetically engineered cells, such as siRNA knockdown cells. For adaptations to your companies' specific needs, please inquire.

Absolutely NO Testing on Animal Skin! Many of the existing tests done in animals can be safely replaced by in vitro products. More details can be found at the ECVAM and ICCVAM web sites under useful links.
AccuSkin can be adapted to high-throughput screening formats and have shown responses on broad classes of compounds similar to human skin. With careful experimental design, pharmacological responses on the following classes of products can be tested on the AccuSkin samples to generate the necessary toxicology, efficacy, or irritancy responses to expedite target selection and validation processes during drug development.
1. Toxicology
2. Cosmetics
3. Personal Care Products
4. Disease modeling
Refer to the application page for proven downstream applications.

AccuSkin Characterization - histology and immunohistochemistry

Below is an image of hematoxylin-eosin stained cross-section of AccuSkin™ followed by immunohistochemical analyses of standard skin biomarkers within AccuSkin cryosections developed using the DAB system.

H&E stained AccuSkin™

Ultrastructural Analysis of AccuSkin

Important features of hemidesmosomes and connective anchoring fibrils in normal skin has been recreated in this two-week old AccuSkin, as demonstrated in the two EM images below. In normal skin (left panel), the network of keratin intermediate filaments (arrows) are seen to connect down to the hemidesmosomes (dark, electron dense structures located along the dermal-epidermal junction). In addition, a fine threads of anchoring fibrils located just beneath the hemidesmosomes are plentiful, with larger collagen filaments in the dermis clearly evident. As shown in the AccuSkin EM image below (right panel), the keratin intermediate filaments pointed by the arrows are connected down to hemidesmosomes located along the basement membrane zone (BMZ) at the dermal-epidermal junction. Long collagen filaments are clearly visible in the dermis. In addition, numerous anchoring fibril network were observed as thin threads just underneath the hemidesmosomes. The presence of these structures represent an efficient true cross-talk between the two cell types within AccuSkin.

Normal Skin AccuSkin

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