Influence of acidic pH on keratinocyte function and re-epithelialisation of human in vitro wounds

Background: Chronic wounds are one of the greatest challenges for the healthcare system. Today, a plethora of dressings are used in the treatment of these wounds, each with specific influence on the wound environment. Due to differences in the permeability of the dressings the use will result in differences in the pH balance in the wound bed. However, little is known about how changes in the pH in the wound environment affect the different phases of the healing process. Aim: The aim of the present study was to investigate the effects of acidic pH on the regeneration phase by studying keratinocyte function in vitro and re-epithelialisation in an in vitro model of human skin. Results:In vitro assays showed reduced viability and migration rates in human keratinocytes when pH was lowered. Real time PCR revealed differential expression of genes related to wound healing and environmental impairment. Tissue culture showed no re-epithelialisation of wounds subjected to pH 5.0 and moderate re-epithelialisation at pH 6.0, compared to controls at pH 7.4. Conclusion: The results indicate that lowering pH down to pH 5.0 in wounds is counterproductive in aspect of keratinocyte function which is crucial for successful wound healing.