(CS-163) Tipping the (pH) scale for achieving wound healing

Introduction: Chronic wounds tend to have alkaline pH values due to persistent inflammation, which causes the breakdown of cellular and tissue components and spillage of alkaline substances into the environment. In turn, this favors the overgrowth of bacteria that also directly contribute to the alkalinization of the milieu, as these conditions are favorable to them. While acidification of the wound bed with substances such as honey, hypochlorous, or acetic acid has met with success, there are concerns that pH values can be lowered beyond physiological values, leading to wound breakdown and impaired healing. Here, we report our experience in using a novel poly-lactic acid (PLA) dermal matrix to promote healing and its effect on lowering the pH of chronic wounds without the addition of other acids.

Methods: A series of 5 patients with chronic wounds received weekly applications of PLA matrices until healing. These matrices contain 75% PLA, which degrades to lactate and lactic acid with a pKa value of 3.85. On every visit, the pH value of the wound bed was recorded using colorimetric indicator strips.

Results: The pH of the patient’s wounds ranged from 7.5 to 9.0 before treatment. After the first week of treatment, the pH values gradually decreased to 7.0-7.5 and remained stable around those values thereafter. The reduction in pH values were matched by significant reductions in the wound size, with the greatest improvement during the first weeks of treatment. All wound fully healed by 8 to 12 weeks without complications, including signs or symptoms suggestive of bacterial overgrowth or infection. Noteworthy, pH values never dropped below physiological parameters over the course of our observation.

Discussion: A wound’s pH value is a good indicator of its healing phase and healing potential. Acidification of chronic wounds contributes to healing by promoting infection control, increase in the immune system antimicrobial activity, modulation of protease activity, increased oxygen availability to the tissue, and direct effects on progenitor cells. Beyond its effects as a CAMP, PLA matrices represent a novel way to acidify wound beds in a sustained manner without the risk of overacidifying the wound bed.