Technology Engineered Skin

Technology

Engineered Skin

Xgene’s CeSSE technology provides a new, simple method for creating a so-called full-thickness skin equivalent. CeSSE , which stands for Cell-Sorted Skin Equivalent (pronounced “cease”), differs from existing methods of creating skin equivalents in that it relies on the body’s own tissue-building mechanisms to create a bi-layered, full-thickness skin equivalent, and this technology is harnessed to create Accuskin^TM, Xgene's proprietary human skin equivalent product.

The Company believes that the CeSSE technology not only creates a superior skin equivalent, but that its simplicity will also make it easier and cheaper to produce commercially. Xgene intends to commercialize the CeSSE technology first in the form of assays with which to test products for their effect on skin and later as skin equivalent for grafting.

Fueling market demand for in vitro skin tests is a worldwide trend away from the use of animals for testing products. Nowhere is this trend stronger than in Europe. In fact, an EEC ban on animal testing (European Economic Community) takes effect in January-2009.

Companies are scrambling to find acceptable alternatives to long-used animal tests. Many large companies, including consumer product conglomerates like Gillette, pharmaceutical giants like Bristol-Meyers Squibb, and cosmetic giants like L’Oreal, are leading the way by actively seeking substitutes for animal tests.

CeSSE

The following two electronmicrographs show normal skin and CeSSE. Although the CeSSE in the picture is only two weeks old, one can see that important characteristics of normal skin are recreated in CeSSE. Under high power examination of normal skin, 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 network of fine threads located just beneath the hemidesmosomes termed anchoring fibrils are plentiful, and larger collagen filaments in the dermis clearly evident.

Normal Skin

In the electronmicrograph CeSSE below, the keratin intermediate filaments (arrows) are seen to connect down to hemidesmosomes located along the BMZ as can be seen below. At the dermal-epidermal interface, seen at high power, clearly visible collagen filaments do develop, as seen by long filaments. In addition, numerous anchoring fibrils were noted on the dermal side just below the hemidesmosomes, seen as thin threads just below the hemidesmosomes. Xgene believes that the presence of these structures will give CeSSE a resistance to the problem of blistering that afflicts most grafts on the market today.

CeSSE

Technology
Skin Products and Services

Skin Products

Our premiere product is the CeSSE in its in vitro configuration. A reconstruction of human skin is available for sale. A “full-thickness” two-layer skin product incorporates both the surface layer, the epidermis, and the deeper layer of skin, the dermis. Typically other firms offer only the epidermal layer of skin for testing. This is because it is very expensive to reconstruct 2 skin layers separately and then sandwich them together to make complete skin, and in any case the resultant skin is deficient. In contrast, Xgene offers human skin made by its unique process that does not contain this defect, and our process requires only a single step allowing us to offer the product at competitive prices. A cross-sectional view of the CeSSE is shown below.

The CeSSE is offered in custom configurations, with a wide choice of skin cell characteristics. Examples of the types of keratinocytes and fibroblasts that can be included are: young or old, normal or diseased, and genetically engineered. In one application, CeSSE technology can be used as an alternative to animal testing, thereby satisfying the tremendous political, legal, and industrial demands for the cessation of animal testing.

CeSSE offered in multi-well formats, version 2.0. (A) hematoxylin/eosin staining of cross-section of human skin made entirely in tissue culture. Panels B-E immunostaining of CeSSE skin using primary antibodies to B ) propyl-4-hydroxylase in dermis C) cytokeratin in epidermis D) collagen IV in upper dermis E ) and laminin at dermal/epidermal interface.

Arrows indicate the dermal-epidermal junction.

Skin Services

The in vivo CeSSE created on the backs of SCID mice has been terminated. We do not conduct nor support any research conducted on laboratory animals! The in vitro CeSSE created in tissue culture is as described above.

· Absolutely NO Testing on Animal Skin! Intact human skin from medical biopsies, obtained as a medical waste product are collected and can be used in certain tests.

· Replacement for Animal Testing on Skin, the CeSSE can be used to test compounds or gene products, and can be adapted to high-throughput screening of a broad variety of compounds on human skin.

· Toxicology

· Cosmetics

· Personal Care Products

· Disease modeling

· CeSSE, with additional development requiring FDA approval, may also have medical grafting applications.

All text, artwork and photos are property of Xgene Corporation