Progenitor cell function
Progenitor cells are the foundation of all epidermal regeneration. With age in vivo, progenitor cell output decreases by up to 50% (Charruyer et al, JID 129, 2009).
In vitro, progenitor cells provide the characteristic colony formation that is required for extended culture longevity. Changes in function can be quantitatively documented by changes in both colony number and colony size.
In addition, colony formation tests also give important additional insights into progenitor cell function, as the morphology and density of the colonies also give important insights into the exact phenotype of the progenitor cells (stem cells, early-stage transient amplifying cells, late-stage transient amplifying cells).