Some investigators have turned to cultured skin, arguing that applying cultured skin to wounds makes more sense than using growth factors because living cells already know how to produce growth factors at the right time and in the right amount. The upper layer contains keratinocytes, the dominant cell type in the epidermis. The lower layer contains collagen and fibroblasts, the main constituents of dermis. Other cell types that trigger immunological response are absent, and, as a result, this engineered tissue is not rejected. Human trials of Apligraf for treating burns, diabetic ulcers, and for use in other skin surgeries are under way.
Cultured skin offers new hope for chronic wounds, but, as with burns, prevention is the best bet.
In addition to its potential as an advanced wound dressing, cultured skin may also prove useful in laboratory testing. FDA has long supported development of such methods, but the state of the science hasn't progressed yet to where it can fully replace animal testing, according to FDA's John Bailey, who heads the Office of Cosmetics and Colors in the agency's Center for Food Safety and Applied Nutrition. Scientists can use isolated skin tissue to test skin penetration, irritation, toxicity, and other effects of various substances. Although cadaver skin works for some purposes, its uses are limited because the cells are dead. Cultured skin contains live, metabolizing cells that can better mimic how skin responds to various stimuli.