A Bioengineered Human Skin Equivalent (hse) for the Evaluation of Protectants

Estimation of permeation of compounds such as chemical warfare agents (CWAs) alone or through barrier creams such as SERPACWA (Skin Exposure Reduction Paste Against Chemical Warfare Agents) requires animal experiments or in vitro testing using animal or human skin. While animal skin does not reflect the same barrier properties as human skin, human skin poses problems of procurement, cost and large variations from donor to donor. Skin equivalents, such as the Human Skin Equivalent (HSE) developed in our laboratory, are in vitro cultured skin models that can be used for permeation/toxicity testing of compounds. The HSE is a full thickness skin equivalent that has been optimized by addition of various growth factors, such as ascorbic acid, lipids and a PPAR-α agonist. It has been characterized for morphology, lipid composition and barrier properties and compared to the commercially available skin equivalents. Compared to these, the HSE possesses closer lipid composition and barrier properties to human skin. The morphology shows a highly differentiated epidermis that provides a good barrier to the permeation of tested model agents such as caffeine. The HSE also provides lower variation in permeability data as compared to human cadaver skin and can be a consistent and reproducible model for permeability testing of agents.