title: Acidic environments may be able to help wounds to heal faster.
abstract: It is assumed that all wounds go through a series of processes such as inflammation, proliferation and remodelling in what is known as the healing cascade. These phases normally result in a healed wound but sometimes one or more of these phases will become 'stuck' so the wound is unable to progress and so becomes chronic. In some cases this may be because of an uncontrolled amount of matrix metalloproteinases (MMPs) in the wound bed. MMPs are enzymes present in wound exudates. In the inflammatory and proliferation stages, they break down dead tissue making it easier for macrophages to do their work of removing dead cells. MMP activity is normally closely controlled by enzyme inhibitors but sometimes this control fails so that MMPs continue to break down new tissues. Laboratory experiments have suggested that this situation is more likely to occur where the wound has a high pH. Application of a weak acid reduces the activity of these out-of-control MMPs.