Abstract
Excessive levels of matrix metalloproteinases (MMPs) are present in chronic wounds preventing wound closure. Reducing detrimental components may be key in healing chronic wounds. Elta Protease-containing wound dressings have been observed clinically to resolve inflammation and appear to aid healing in acute and chronic recalcitrant wounds. To investigate possible mechanisms of action, in vitro tests, zymography, collagenase assays and enzyme-linked immunosorbent assays (ELISAs), were performed to evaluate the effect of the dressing proteases on detrimental and beneficial wound healing components such as MMPs, Tissue Inhibitor of Matrix Metalloproteinases (TIMPs), cytokines and growth factors. Standards of pro- and active MMP-2, MMP-9 and chronic wound fluid (CWF) were prepared. Degradation of target proteins was enhanced by increased Elta Protease concentration, temperature and incubation time. Incubation with serial dilutions of the Elta Proteases resulted in nearly complete degradation of all MMP standards. After a 30-minute incubation, twofold diluted Elta Proteases degraded >90% of the gelatinases in CWF. ELISAs showed that Elta Proteases effectively degraded MMP-9 and tumour necrosis factor (TNF-alpha). In contrast, Platelet Derived Growth Factor (PDGF) and interleukin 1 beta were resistant to degradation by Elta Proteases. These results suggest that Elta Protease dressings appear to deactivate detrimental components in CWF, which may reduce wound bed contact with harmful proteins.