Skin Irritation
EpiDerm™ In Vitro Skin Irritation Measurement
The EpiDerm human skin tissue model was introduced over 10 years ago in response to demand for an in vitro (non-animal) alternative to the animal-based Draize skin irritation test used in the cosmetics, personal care, and household products industries.
The driving forces behind this movement included humane objections to animal testing, as well as the equally important need for a measurement system that produced quantitative, reproducible results. Also, introducing a skin irritation test derived from human skin cells was important because, in many instances, results obtained using animal-based testing do not correlate well with the actual response seen in human tissue.
Key EpiDerm Tissue Model Features:
Human Skin Cell-Derived Model
The responses elicited by test materials using the EpiDerm tissue model more closely approximate the skin irritation responses that are seen in human subjects.
Metabolically Active
Again, responses to test materials more closely mirror real-world skin irritation responses, versus the use of human cadaver skin.
Excellent In Vitro-to-In Vivo Correlation
In a just-completed European study of in vitro alternatives for measuring skin irritation potential, EpiDerm once again performed well in this critical area, posting a study-best coefficient of correlation of 0.94.
Objective, Quantifiable Endpoints
Animal testing skin irritation "end points" are typically comprised of human observation of the condition of the test animal's skin after exposure to test material(s), and the ranking of that observation in an arbitrary, qualitative way. The EpiDerm skin irritation test endpoint is based on the widely accepted, highly quantifiable MTT ET-50 Assay1.
Reproducible - lot-to-lot, year-to-year
EpiDerm has been produced continuously for over 10 years, with lot-to-lot QC data dating back that far. No other manufacturer of in vitro tissue models can provide such a solid, well documented foundation on which to base one's skin irritation testing.
Validated by ECVAM
In April 2007, the ECVAM (European Centre for the Validation of Alternative Methods) Scientific Advisory Committee (ESAC) unanimously endorsed the following statement on the use of EpiDerm for the determination of Skin Irritation: “The EpiDerm model reliably identifies skin irritants. Negative results may require further testing (e.g. according to the tiered strategy, as described in the OECD TG 404).”
Explanation of Terms in ECVAM/ESAC Statement:
"Negative results" means "no irritation".
"Tiered strategy" as defined in the Supplement to Test Guideline 404, "A Sequential Testing Strategy for Dermal Irritation and Corrosion", is a one animal confirmatory study to be run when a negative (no irritation) result is obtained with EpiDerm.
NOTE: MatTek is developing a protocol for validation that will eliminate the need for additional "false negative" testing.
EpiDerm Description
EpiDerm is a normal (non-transformed), human cell-derived, metabolically active, 3-dimensional organotypic in vitro skin model. It closely mimics human epidermis, both structurally and biochemically, and does so in a very reproducible manner. Proven EpiDerm skin irritation protocols, based on the well-documented MTT ET-50 assay, allow researchers to quantitatively measure the dermal irritancy of their experimental materials.
Types of materials that have been tested using the EpiDerm system include cosmetics and their constituents, household products, and pharmaceuticals (link to extensive list given below).
Major companies on the EpiDerm user list include Clairol, Johnson & Johnson, Procter & Gamble, Revlon, SmithKline Beecham and Unilever.
EpiDerm Skin Irritation Test Overview
EpiDerm tissues are removed from a Model EPI-200 Kit (24 samples per kit), dosed with test materials in duplicate, and exposed for 2, 5, and 18 hours (duplicate negative controls are dosed for 5 hours). At the end of each dosing period, those tissues exposed for that time period are removed from the incubator, test materials are removed from those tissues, and the tissues are tested for viability using the MTT ET-50 Assay1. If desired, additional testing for specific cytokines related to skin irritation determination can also be performed. A detailed test protocol is available--please contact MatTek to receive a copy.
EpiDerm Skin Irritation Technical References
Clicking on the link below will open a page that contains links to over 45 technical references describing the development, characterization, and use of this innovative human skin irritation measurement system. (Click on the TR number highlighted in blue to review that technical reference.)
Link to ALL EpiDerm Skin Irritation Technical References
Key technical references (TR's) within that group include:
TR-270 - PREDICTIVE ABILITY OF RECONSTRUCTED HUMAN EPIDERMIS EQUIVALENTS FOR THE ASSESSMENT OF SKIN IRRITATION OF COSMETICS
TR-187 - IL-1α AND IL-1ra SECRETION FROM EPIDERMAL EQUIVALENTS AND THE PREDICTION OF THE IRRITATION POTENTIAL OF MILD SOAP AND SURFACTANT-BASED CONSUMER PRODUCTS
TR-179 - TESTING AND IMPROVEMENT OF RECONSTRUCTED SKIN KITS IN ORDER TO ELABORATE EUROPEAN STANDARDS: FIRST RESULTS
TR-136 - A REPRODUCIBLE, STRUCTURALLY APPROPRIATE SKIN MODEL FOR DERMAL IRRITANCY AND EFFICACY TESTING
Extensive List of Materials Tested for Skin Irritation
Click on the link below to view representative list of the materials MatTek and others have tested using the EpiDerm tissue model.
Materials Tested using EpiDerm
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Next Steps:
Contact MatTek today to learn more about the EpiDerm In Vitro Human Skin Irritation Measurement System.
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EpiDerm Data Sheet
EpiDerm Product Specifications
EpiDerm Technical References
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1. MTT ET-50 Tissue Viability Assay - A colorimetric assay system that measures the reduction of a yellow tetrazolium component (MTT) into an insoluble purple formazan product by the mitochondria of viable cells. After incubation of the cells with the MTT reagent for several hours, a solution is added to lyse the cells and solubilize the colored crystals. Samples are read using an ELISA plate reader at a wavelength of 570 nm. The amount of color produced is directly proportional to the number of viable cells. ET-50 refers to the time required to reduce tissue viability to 50%.
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