02-04-2013: In an advance in efforts to reduce the use of animals in testing new cosmetic and other product ingredients for skin allergies, scientists are describing a new, highly accurate non-animal test for these skin-sensitizers. Their study appears in ACS' journal Chemical Research in Toxicology.
Bruno Miguel Neves and colleagues explain that concerns about the ethics and costs of animal-based tests for skin sensitizers, plus regulations in the European Union, are fostering a search for alternative tests. Testing product ingredients prior to marketing is important, because allergic contact dermatitis is the most prevalent form of immunotoxicity in humans.
The scientists describe development of a cell-based alternative test that enlists genes and signaling pathways in mouse skin cells growing in the laboratory. Exposure to skin sensitizers triggers characteristic responses, activating genes and making cells release substances that communicate with adjacent cells. Evaluation of the test on 18 compounds showed that it had a sensitivity of 92 percent in correctly identifying actual sensitizers. It had a specificity of 100 percent and did not produce any false positive results — indicating that a substance caused sensitization when, in fact, it did not. The approach could be "extremely valuable" in revealing the interaction of skin cells with sensitizers, the scientists say.