Des Cave, from BioReliance, the largest genetic toxicology group in the world, outlined the three assays at a recent industry event - the Cosmetics Consultants Europe group’s Open Academy in Barcelona.
The three alternative methods are:
3D Skin Micronucleus assay
3D Skin comet assay
Cave asserts that in vivo assays being unavailable for cosmetics testings means the industry needs more complex, rigorous and sophisticated in vitro tests.
He explains genetic toxicity is a key area of focus for testing, and alternatives to animal testing have been in high demand since the practice was outlawed across Europe in 2013.
“The testing of cosmetics for genetic toxicity is a critical part of the safety testing of cosmetics and ingredients,” Cave confirms.
3D Skin Micronucleus assay
This testing method relies on a 3D skin model, a constructed epidermis that shares the structure of a piece of skin, making it much more natural than a flat layer of cells for testing.
A 3D model show in vivo-like behaviour, Cave explains, making it a better representation of how the skin will respond in reality. One company producing 3D skin models is MatTek.
The micronucleus testing process with a 3D skin model is ‘exactly the same’ as that of a normal in vitro miconucleus test, according to Cave, but gives a better representation of how the skin responds, rather than testing on flat cells.
3D Skin Comet assay
Again, this method applies the standard comet assay (OECD 489) but applied to a 3D model again. This time, the skin model is thicker, with the chemical applied directly to the skin.
Cave explains that the skin sample is treated exactly the same as in an in vivo test, measuring the DNA tail in the sample after the chemical is applied.
The CANMultiflow assay tests for DNA damage, cellular proliferation (which can lead to cancer), and polyploidy.
Along with the two 3D model assays, this approach will be the basis of the future for genotox analysis, Cave predicts, though each assay has limitations.
A lot of data is needed for CANMultiFlow to provide accurate testing, for example, with the technology learning as it goes.
The future of testing?
All three methods give you a much more complex, realistic model when compared to 2D cells on a plate, Cave asserts. They have phase 1 and phase 2 metabolising enzymes, a structure, blood vessels and a stratum corneum, he notes.
“These really are the way forward for cosmetics testing, this is really where we’re going to go,” he asserts. “They are complementary, no one can be said to be better than the other.”
What is the Open Academy?
The CCE’S Open Academy first edition (16 October 2017) saw a series of eminent experts from across the industry Europe present on various hot topics.
Highlights include presentations on non-animal testing methods for next generation ingredients, software tools for formulation and regulatory affairs, and CPR, REACH and Brexit. Further information on the CCE can be found here.