# An Update on the Correlation Between Neuroimmunomodulation, Photodynamic Therapy (PDT), and Wound Healing: The Role of Mast Cells

## TL;DR

This review explores how photodynamic therapy affects wound healing by interacting with the nervous system and immune cells, particularly mast cells.

## Contribution

The paper highlights the novel role of mast cells as neuroimmune intermediaries in photodynamic therapy's effect on chronic wound healing.

## Key findings

- Mast cells act as key neuroimmune intermediaries by releasing inflammatory mediators that influence wound tissue and nerve fibers.
- Photodynamic therapy modulates wound healing through cellular and molecular mechanisms linked to neuroimmunomodulation.
- Neuropeptides from peripheral nerves further modulate immune activity and tissue repair during wound healing.

## Abstract

This review presents some aspects of the complex relationship between neuroimmunomodulation, photodynamic therapy, and wound healing. This relationship is important because photodynamic therapy, currently used to treat chronic wounds, has numerous effects on so-called neuroimmunomodulation, or the influence the nervous system has on immune cells. Consequently, the cellular and molecular mechanisms of wound healing and the alterations of these mechanisms that lead to the formation of chronic wounds are first considered. This view is subsequently broadened to include the effects produced by neuroimmunomodulation throughout the various phases of wound healing and the alterations produced in chronic wounds. Throughout the above, the role of mast cells, the main inflammatory cells that play a key role in wound healing, is highlighted. In this context, mast cells, located in close anatomical and functional proximity to peripheral nerve endings, act as key neuroimmune intermediaries. Upon activation, mast cells release inflammatory mediators that directly influence wound tissue and sensitize nearby nerve fibers. In turn, peripheral nerves release neuropeptides that further modulate immune cell activity, vascular responses, and tissue repair processes. All of this is in turn linked to the clinical evidence that photodynamic therapy, by virtue of the cellular and molecular mechanisms involved, can indeed be considered involved in the healing of chronic wounds.