Protease and pro-inflammatory cytokine concentrations are elevated in chronic compared to acute wounds and can be modulated by collagen type I in vitro.

Physiological wound repair is a highly regulated, complex process, which leads to formation of new tissue after injury. However, the healing process is not perfect and healing impairments can occur. Delayed healing and formation of chronic wounds has been linked to the excessive production of proteolytic enzymes leading to reduced amounts of growth factors and successive destruction of the extracellular matrix. It has been implied that there is an alteration in the normal control mechanisms regulating the levels of these enzymes. The study presented provides data on the concentration of proteases and cytokines in wound fluid from chronic when compared with acute wounds. Levels of proteases such as PMN elastase, matrix metalloproteinases-2 (MMP-2), and MMP-13 were found to be profoundly elevated in chronic when compared with acute wound fluids. In addition, concentrations of IL-1beta, IL-6, and IL-8 were shown to be significantly higher in chronic than in acute wounds. Furthermore, the ability of a wound dressing, consisting of bovine collagen type I, to bind pro-inflammatory cytokines was investigated. Collagen type I was able to bind significant amounts of the pro-inflammatory cytokines in vitro. Thus, it should be able to establish a more physiological wound milieu in vivo and promote healing.