THE SEARCH FOR ALTERNATIVES TO ANIMAL TESTING
For decades, pharmaceutical, cosmetic and chemical industries have used animal experimentation to provide adequate documentation on the safety and toxicity of their products. However, changes in regulations on animal experiments required them to change their testing tools and find new alternatives to animal testing to evaluate the effects of their products and ingredients on human skin.
New alternatives to animal testing
Several alternative testing methods have been developed to avoid animal experiments and allow industries to test the effects of their products on human skin. The following sections present two alternative testing methods according to their current capacity to mimic real human skin.
Ex Vivo Human Skin Models
Genoskin’s innovative human skin models provide a new alternative to animal testing. All our human skin models use real human skin that is donated after surgical operations. The donated skin is placed into a multi-well testing kit and kept alive for 7 days to allow for repeated topical applications. Our human skin models hold major characteristics (mature stratum corneum, presence of minority cell populations like Langerhans cells or melanocytes, epidermal appendages such has hair follicles and sweat glands, normal dermal extracellular matrix…), and functions (skin barrier, melanogenesis, epidermal proliferation and differentiation, hair growth, sebum production…) of human skin in order to correctly mimic in vivo human skin. They are the closest alternative to in vivo clinical testing that is currently available on the market.
Reconstructed human skin models
In vitro reconstructed human epidermis (RHE) models are considered valuable alternatives to animal testing and several OECD guidelines refer to these models to study the effects of certain products on human skin.
Even though some of these RHE models have been validated for skin corrosion and skin irritation testing, none of the current RHE models are able to reproduce the complexity of in vivo human skin and mimic its 3-dimensional organization. More specifically, RHE models miss certain cell types, skin appendages, structures and functions, such as:
All these inherent active constituents influence normal human skin physiology, such as immuno-modulative response, regulation of skin surface temperature… Moreover, most reconstructed human skin models only contain epidermal keratinocytes and/or dermal fibroblasts and only a few specialized models include other cell types such as melanocytes.
In view of the limitations present in RHE models, the Scientific Committee on Consumer Safety (SCCS) in Europe considers their use as being “under development,” noting that such systems “are not yet advised for in vitro testing on the basis of their insufficient barrier function.”