April 27, 2014
Our skin, specifically the epidermis – the outermost layer of skin – is what protects us from our environment. Though soft and occasionally very squishy, it is our armor. It prevents water from escaping as well as keeps microbes and toxins out. Our skin is a complex coating that has been thus far unable to be replicated. Tissue engineering has not been able to grow artificial epidermis with the same functional barrier as our own that would be needed for drug testing, and has been further hindered in producing a lab model for large-scale drug screening by the number of cells that can be produced via a single skin biopsy sample. However, an international team led by King’s College London and the San Francisco Veteran Affairs Medical Center (SFVAMC) has recently created the very first lab-grown epidermis. This new skin, grown from human pluripotent stem cells, will offer a cost-effecting alternative for testing new drugs and cosmetics, and it could also help to discover new therapies and treatments for various forms of skin disorders.
“The ability to obtain an unlimited number of genetically identical units can be used to study a range of conditions where the skin’s barrier is defective due to mutations in genes involved in skin formation, such as ichthyosis or atopic dermatitis,” says Dr. Theodora Mauro, the leader of the SFVAMC team. “We can use this model to study how the skin barrier develops normally, how the barrier is impaired in different diseases and how we can stimulate its repair and recovery.”
In this study, the use of human induced pluripotent stem cells, or iPSC, could produce an unlimited supply of pure keratinocytes, which are the predominant cell type found in the epidermis, that closely resemble the keratinocytes generated from human embryonic stem cells, hESC, and the primary keratinocytes from skin biopsies with no real significant differences in the structure or functional properties between them. In short, though produced using different stem cells, they all worked the same, only these new ones can be produced much more easily and in far greater quantities. These newly created keratinocytes were used to manufacture 3D epidermal equivalents in a high-to-low humidity environment in order to build a functional permeability barrier, which is what our own bodies use to keep us from losing moisture and to keep out harmful chemicals.
According to Dr. Dusko Ilic, leader of the King’s College London team, “Our new method can be used to grow much greater quantities of lab-grown human epidermal equivalents, and thus could be scaled up for commercial testing of drugs and cosmetics. Human epidermal equivalents representing different types of skin could also be grown, depending on the source of the stem cells used, and could thus be tailored to study a range of skin conditions and sensitivities in different populations.”
All in all, this is an exciting new breakthrough for a great many reasons. Not only could thus help in studying various skin conditions, but it could also help to limit animal testing of cosmetics, as they will simply be able to use this new, artificially made flesh rather than lab animals.
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