The chronic wound can be characterised as an environment with excessive proteolytic activity and low protease inhibition capability, resulting in the degradation of many potentially pro-healing protein components, including growth factors and adhesion molecules. This non-healing wound is associated with an imbalance in matrix metalloproteinase (MMP) activity, which is thought to degrade newly formed extracellular matrix and interfere with the pro-healing activities controlled by growth factors and cytokines.
...and the Corneal Model
Although wound healing carries the obvious primary connotation of dermal related wounds; wound healing does not lie solely in the domain of the dermal response. Mucosal surfaces and specifically the cornea, present other important examples of wound healing sites. The cornea, like skin, is at the anterior surface of the body and acts as a barrier against the external environment. There are several similarities between the ocular environment and wound bed with irresistible comparisons to be drawn between the configurations of: wound bed/wound fluid/dressing on one hand, and cornea/tear film/contact lens on the other.