The extracellular matrix provides the structural basis for the dermis.
The morpholoy of the ECM in the dermis varies significantly between the upper and lower layers. The lower reticular dermis is characterized by a dense and coarse collagen network. In comparison, the upper papillary dermis is thinner, and typically exhibits a finer morphology.
Active ingredients may directly affect either collagen production, or alternatively the collagen turnover mechanisms, based on the MMP family of proteinases that breakdown and actively remodel the ECM.
Both collagen production and MMP activity can be evaluated in fibroblasts using colorimetric tests in 96 well plates.