An Outgrowth Culture System of Normal Human Epithelium: An In Vitro Model to Study the Coordination of Cellular Migration and Proliferation

In order to study the growth regulation of normal human epithelium, we have developed an outgrowth culture system ( 1 ). Cinematographic observation has revealed that the cells migrate and proliferate in a coordinated manner. For example, an outgrowth will expand concentrically as a cell sheet, and the cell density will be consistent between different sized outgrowths ( see Fig. 1 ). The increment in the radius of the outgrowth stays constant (about 1.5 mm/d) and is independent of the size of the explant or donor individuals. We can easily obtain 10 ⁸ cells per specimen in 3 wk. Because of its constant growth pattern, the growth history of the cultures can be easily traced, and comparable cultures can be used for further analyses ( see Note 1 ).

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