Human skin model test

OECD. Test guideline 431 In Vitro Skin Corrosion Human Skin Model Test, OECD, Paris, 2004. 

Two in vitro tests for the assessment of skin corrosion, the Transcutaneous Electrical Resistance [TER] Assay (TG 430) and the human Skin Model Test (TG 431) (Section... 

In vitro skin corrosion Human skin model test... 

The OECD and EU have developed specific test guidelines for in vitro/ex vivo testing of skin corrosion, the Transcutaneous Electrical Tesistance (TER) Test and the Human Skin Model Test (see Table 4.7). In fact, the EU Annex V, B.40 test guideline includes the two adopted OECD in vitro tests for skin corrosion (TG 430 and 431). OECD has also developed a third test guideline for skin corrosion, the In Vitro Membrane Barrier Test this test guideline has not yet been adopted. 

The principle of the human skin model test is that the test material is apphed topically for up to 4h to a three-dimensional human skin model, comprising at least a reconstructed epidermis with a functional stratum comeum (outermost layer of the skin). The human skin models can come from various sources, but they must meet certain criteria. Corrosive materials are identified by their abdity to produce a decrease in cell viabdity (as determined, e.g., by using a dye reduction assay) below defined threshold levels at specified exposure periods. The principle of the test is in accordance with the hypothesis that corrosive chemicals are able to penetrate the stratum comeum (by diffusion or erosion) and are sufficiently cytotoxic to cause cell death in the underlying cell layers. 

Organization for Economic Co-operation and Development (OECD), OECD Guidelines for the Testing of Chemicals No. 431 In vitro Skin Corrosion — Human Skin Model Test, Paris, France, 2002b. 

Furthennore, some materials, including medical textiles, have the potential to cause allergy or irritation. The sensitization potential of the material is therefore required to be tested. The ISO 10993-10 assesses the possible contact hazards from chemicals released from the devices, which may produce skin, mucosal, or eye irritation and skin sensitization. Currently, there has been no satisfactory in vitro test to eliminate the requirement for in vivo testing to evaluate irritation. However, the rat skin Transcutaneous Electrical Resistance (TER) test and the human skin model test have been internationally validated and accepted as alternative tests to assess the skin corrosion with chemicals (OECD, 2009a,b). To perform the test, an animal (rabbit) with the healthy intact skin needs to be used and the fur on the back of animal is clipped 24-4h of testing with approximate size of 10cmX 15 cm and then 0.5g or 0.5 mL of materials apply to the site and then the application site is covered with... 

SkinEthic human skin model for skin corrosivity testing EU... 

To test the irritancy potential of substances, two tests which can reliably distinguish between skin corrosives and noncorrosives are endorsed by the European Centre for the Validation of Alternative Methods (ECVAM). The testing procedures are based on the transcutaneous electrical resistance (TER) measurements of rat skin and on a human skin model. Both test systems [141-145] will be briefly outlined below. Nevertheless, these tests are not suited for the group of mild irritants which do not induce an acute effect on the barrier function. For those substances, new markers need to be evaluated. First results are available for heat shock protein 27 where higher levels were observed in skin models after exposure to mildly irritating chemicals [146, 147]. 

The human skin model assay involves measuring the effects of corrosives on viable cells in a reconstituted human skin equivalent. To be accepted as a valid human skin model, several criteria must be met. The artificial skin must comprise a functional stratum corneum with an underlying layer of viable cells. Furthermore, the barrier function of the stratum corneum, as well as the viability of the epidermis, must be verified with appropriate experimental setups. The chemicals to be tested are applied up to 4 h as a liquid or a wet powder onto the skin model. Afterwards, careful washing has to be performed, followed by investigation of the cell viability [e.g., with a (MTT)] reduction assay). 

The human skin model assay can provide further data on the degree of corrosiveness and allows ranking corrosives among each other. It is, therefore, accepted as a replacement method of animal tests for skin corrosion in the EU. 

A further option to investigate the phototoxic potential of substances is the use of reconstructed human skin models. The evaluation of the cell viability is based on the MTT-assay that is sensitive for the mitochondria activity in cells. Currently, these in vivo substitutes are still under validation and are not approved as full standard test methods for the investigation of the phototoxicity potency of a test chemical. However, several existing models are in use for prevalidation studies and are described elsewhere in more detail [92],... 

For in vitro testing the Organisation for Economic Cooperation and Development (OECD) approved in 2004 test guideline 428 [37], which currently advocates the use of human, rat, and pig skin to measure cutaneous absorption by a vertical diffusion system (Franz cell). Dmg concentrations are followed in an acceptor fluid separated by the skin from the donor vehicle, which is applied to the external surface of the skin. Instead of human or animal skin, human skin models could be used as soon as the equivalence of their results are proven. Comparative studies indicate a correlation of penetration data in vitro and in humans [38]. 

EU test method B40, Skin corrosion in vitro), which includes two in vitro tests for skin corrosion, the rat skin TER assay and a test employing a human skin model (Section... 

Flamand, N., Marrot, L., Belaidi, J.P., Bourouf L., DouriDe, E., Feltes, M. and Meunier, J.R. (2006) Development of genotoxicity test procedures with Episkin, a reconstructed human skin model towards new tools for in vitro risk assessment of dermally applied compounds Mutation Research, 606, 39-51. 

The development of a tiered testing strategy for predicting a particular kind of toxic potential, skin corrosion, based on the sequential use of a QSAR a PM based on physicochemical (pH) data and a PM based on in vitro data obtained with the EPISKIN test, a particular type of human skin model... 

Kirsch-Volders M, Decordier I, Elhajouji A, Plas G, Aardema MJ et al (2011) In vitro genotoxicity testing using the micronucleus assay in cell lines, human lymphocytes and 3D human skin models. Mutagenesis 26 177-184... 

EPISKIN human skin model (commercial system) Reconstructed human epidermal Cell viability (MTT-test) B.40/OECD TG 431... 

In the past, skin corrosion was assessed using animal studies (OECD TG 404, 2002) but recently three in vitro tests for skin corrosivity are used. The rat skin transcutaneous electrical resistance (TER) assay and a test employing a human skin model are included in Annex V of the Dangerous Substances Directive (Directive 2000/33/EC, B.40. Skin corrosion) and also proposed as an OECD draft for testing guidelines TG 430 (OECD, 2004a) and TG 431 (OECD, 2004b) (Table 9.1.1). 

The reconstructed human skin models are three-dimensional models generated by growing keratinocyte cultures at the air-Uquid interface on various substrates and that enable the topical application of either neat or diluted test materials. 

The test material is applied topically for up to 4 h to a three-dimensional human skin model, comprising a reconslructed epidermis with a functional stratum comeum (Eigure 9.1.2). Eor liquid (a minimum of 25 /il/cm ) and solid materials, sufficient test substance must be applied to cover the skin surface. 

Consequently, the human skin model assays (e.g. EpiDeim and EPISKIN ) and the mouse SIFT appear to be the most promising in vitro methods for skin irritation testing. However, there is a need to develop new endpoints that are more predictive of skin irritation than simple cytotoxicity determinations. 

Botham P. A., L. K. Earl, J. H. Fentem, R. Roguet and J. J. M. van de Sandt, 1998, ATLA 26, 195. Earl L. K., T. J. Hall-Manning and G H. Holland, 1999, Alternatives to Animal Testing II. Proceedings of the Second International Scientific Conference Organised by the European Cosmetic Industry, The Determination of Acute Chemically Induced Skin Irritation Using a Human Skin Model, Eds. D. G. Clark, S. G. Lisansky and R. Macmillan, CPL Press, Newbury. 

H. Kandarova, M. Liebsch, H. Spielmann, E. Genschow, E. Schmidt, D. Traue, R. Guest, A. Whittingham, N. Warren, A. O. Gamer, M. Remmele, T. Kaufmann, E. Wittmer, B. De Wever, and M. Rosdy. Assessment of the human epidermis model SkinEthic RHE for in vitro skin corrosion testing of chemicals according to new OECD TG 431. Toxicol. In vitro 20 547-559 (2006). 

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