The Use of a Proprietary Near-Infrared Laser to Enhance Wound Healing: A Preliminary Preclinical and Clinical Study

Abstract

Background: Nonthermal light energy has been used to enhance wound healing. This is known as photobiomodulation. Although preclinical evidence is largely based on laser light, light-emitting diodes (LEDs) form the mainstay of clinical studies owing to the lack of available lasers for nonclinical use. However, it is speculated the 2 technologies exhibit dissimilar biological responses.

Objectives: The influence of a new, commercially available near-infrared laser device on the gene expression profile of human skin relative to an equivalent, near-infrared LED device was evaluated. Additionally, the wound healing potential of the device was examined in practice.

Methods: Defatted human skin was exposed to the laser (3), LED (3), or negative control (3) for 5 days. On Day 6, skin samples were biopsied for ribonucleic acid extraction and gene expression assays run for 107 genes of interest. Twenty patients with chronic wounds were randomized to receive standard wound care ± laser therapy 3 times weekly for 4 weeks, and wounds were analyzed for healing.

Results: The laser altered expression of 45 genes. Highly up-regulated genes (>5-fold change) included those implicated in wound healing and antiaging, whereas highly down-regulated genes included those implicated in inflammation and extracellular matrix integrity. The LED device altered expression of only 1 gene relative to negative controls. The laser reduced mean wound area by 78% and healed 4 of 10 wounds completely. In contrast, 8 of 10 of those receiving standard care exhibited no change.

Conclusions: A proprietary near-infrared laser exhibited superior ability to influence gene expression in healthy skin than an equivalent LED device and induced the healing of chronic wounds.

Figure 1.

A comparison of wound healing in chronic wounds with and without exposure to NIR laser. Patient 2 (74-year-old female; trochanteric pressure sore) (A) before and (B) after 4 weeks of standard dressings only. Patient 9 (69-year-old male; lower extremity vascular ulcer) (C) before and (D) after 4 weeks of standard dressings only. Patient 11 (67-year-old male; below-knee amputation stump) (E) before and (F) after 4 weeks of standard dressings with NIR laser therapy at dressing changes. Patient 12 (71-year-old female; sacral pressure sore) (G) before and (H) after 4 weeks of standard dressings with NIR laser therapy at dressing changes. NIR, near infrared.