| Exudate component/Characteristic | Level in non-healing wounds (incomparison with healing/acute wounds) | Comments |
| Pro-inflammatory cytokines | Higher | Cell-signalling molecules (cytokines) that stimulate the inflammatory process can increase levels of MMPs in relation to the levels of the proteins that inhibit MMP activity; in effect this increases MMP activity |
| Matrix metalloproteases*:MMP-2 and MMP-9 | 10-25 x higher | High levels of MMPs may result in degradation of growth factors; if rates of extracellular matrix (ECM) degradation match or exceed rates of ECM production, healing can be slowed or halted |
| Growth factors | Lower | Growth factors stimulate the proliferation and migration of cells involved in new blood vessel formation, epithelialisation, wound contraction and the deposition of extracellular matrix. In non-healing wounds, levels of growth factors are lower than in healing wounds, probably mainly because of degradation by proteolytic enzymes |
| Mitogenic activity** | Lower | Proliferation of fibroblasts (mitosis), a key aspect of wound healing, is stimulated to a much lower extent by fluid from non-healing wounds than by fluid from healing wounds |
Table 2: Examples of differences in wound exudate composition between non-healing and healing wounds
(Yager et al, 1996; Trengoveet al, 1999; Trengove et al, 2000; Barrientos et al, 2008; Schultz et al, 2011; Stacey, 2018)
*Matrix metalloproteases (MMPs) are released by macrophages, endothelial cells and epidermal cells and degrade proteins, including those in the extracellular matrix.
**Ability of wound exudate to stimulate fibroblast proliferation.





