The Effect of pH on the Extracellular Matrix and Biofilms.

Significance: Chronic wounds become caught in a state of inflammation causing an increase in levels of degrading proteases, which destroy components of the extracellular matrix (ECM) that are essential for the wound healing process. This review aims to highlight and provide readers with an overview of what is currently known about the role of pH and its effect on the ECM and biofilms within healing and nonhealing wounds. Recent Advances: The pH profiles of healthy skin, acute wounds, and chronic wounds differ significantly. Chronic wounds have an alkaline pH whereas healthy skin has a slightly acidic pH. Although there is evidence on the effect of pH on protease production and bacterial proliferation in wounds, there is little evidence to show its effect on ECM synthesis and degradation. Critical Issues: The implications for the complex nature of chronic wounds are that no single treatment is relevant for all wounds, but rather a combination of methodologies must be adopted. It is known that pH of a wound reduces throughout the stages of healing, suggesting that wound pH measurements could be beneficial to identify nonhealing wounds earlier and decide on the most appropriate course of treatment. Future Direction: Wound healing is a very complex process with multiple factors known to play a role. All aspects of the nonhealing wound (defective ECM, pH, microbial invasion, and excess proteases) need to be taken into account when investigating or clinically treating a chronic wound.