In a major breakthrough, scientists have been successful in developing the first lab-grown epidermis - the outermost skin layer - which could replace animals in drug and cosmetics testing.
The new epidermis, grown from human pluripotent stem cells (iPSC), could also help develop new therapies for rare and common skin disorders.
The research, done by King's College London and the San Francisco Veteran Affairs Medical Center (SFVAMC), describes the use of human induced iPSC to produce an unlimited supply of pure keratinocytes - the predominant cell type in the outermost layer of skin.
This closely matches keratinocytes generated from human embryonic stem cells (hESC) and primary keratinocytes from skin biopsies.
"These keratinocytes were used to manufacture 3D epidermal equivalents in a high-to-low humidity environment to build a functional permeability barrier, which is essential in protecting the body from losing moisture, and preventing the entry of chemicals, toxins and microbes," explained Theodora Mauro, leader of the SFVAMC team.
The epidermis, the outermost layer of human skin, forms a protective interface between the body and its external environment, preventing water from escaping and microbes and toxins from entering.
"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 barrier formation, such as ichthyosis (dry, flaky skin) or atopic dermatitis," Mauro emphasised.
"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," he noted.
"The 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," added Dusko Ilic, leader of the team at King's College London.
The study was published in the journal Stem Cell Reports.
