Photodynamic Therapy With RLP068 and 630-nm Red LED Light in Foot Ulcers in Patients With Diabetes: A Case Series

Deep Red-Light-Mediated Nitric Oxide and Photodynamic Synergistic Antibacterial Therapy for the Treatment of Drug-Resistant Bacterial Infections

Infections caused by persistent, drug-resistant bacteria pose significant challenges in inflammation treatment, often leading to severe morbidity and mortality. Herein, the photosensitizer rhodamine derivatives are selected as the light-trapping dye and the electron-rich substituent N-nitrosoaminophen as the nitric oxide (NO)-releasing component to develop a multifunctional (deep) red-light activatable NO photocage/photodynamic prodrug for efficient treatment of wounds and diabetic foot infections. The prodrug, RhB-NO-2 integrates antimicrobial photodynamic therapy (aPDT), NO sterilization, and NO-mediated anti-inflammatory properties within a small organic molecule and is capable of releasing NO and generating Reactive oxygen species (ROS) when exposed to (deep) red laser (660 nm). This strategy overcomes the limitation of using a single photosensitizer, which is often inadequate for eliminating drug-resistant bacteria. Additionally, it demonstrates that NO released from the prodrug can interact with superoxide anions (O2 •-) generated by PDT to form a more reactive and oxidative agent, peroxynitrite (ONOO-). These three components act synergistically to enhance the antimicrobial effects. Furthermore, the released NO can inhibit the NF-κB pathway by regulating the expression of toll-like receptor 2 (TRL2) and tumor necrosis factor-α (TNF-α), thereby alleviating tissue inflammation. The developed prodrug ， RhB-NO-2 has the potential to expedite the healing of superficial infected wounds and offer a promising approach for treating diabetic foot ulcers (DFUs).

Antimicrobial Photodynamic Therapy in the Treatment of Diabetic Foot Ulcer: A Scoping Review

Objective: To map the literature about photodynamic therapy in treating diabetic foot ulcers. Background: Diabetic foot ulcers get constantly infected, thus culminating in hospitalizations and amputations. Photodynamic therapy is an antimicrobial treatment that may assist in the healing process. Materials and Methods: A search of nine electronic information sources was made as determined by the Joanna Briggs Institute. Two independent researchers accomplished a screening of studies with the support of Rayyan. The data were analyzed through Iramutec®. Results: The sample consisted of 27 studies. Photodynamic therapy was identified as safe and effective, with the ability to reduce pain, edema, exudate, extent of the injury region, microbial load, and the risks of infection, osteomyelitis, and amputations. Conclusions: The capacity of photodynamic therapy to relieve symptoms, decrease risks of complications, and accelerate the healing process highlights its potential positive impact on clinical practice.

The Effect of Low-Frequency Magnetic Fields with Low Induction and Red LED Light on Keratinocyte Biological Activity-An In Vitro Research Model

For several decades, there has been growing interest in the influence of low-frequency magnetic fields (LFMFs) and red LED light on the healing process. Keratinocytes are cells that play a significant role in the process of wound healing and tissue regeneration. A human keratinocyte cell line (HaCaT) was exposed to an LFMF with low induction (180-195 Hz; 60 µT, magnetostimulation), red LED light (630 nm; 300 mW, LED therapy), and their combined action (magneto-LED therapy) in in vitro culture conditions. On day 4 and 8 of the experiment, the following parameters were determined: adhesion/proliferation, adenylate kinase (AK), nitric oxide (NO), cytokines (IL-1β, IL-6, IL-8, IL-10, IL-12p70, TNF-α), metalloproteinases (MMP-2, MMP-9), and collagen IV. It was shown that magnetostimulation caused an increase in keratinocyte adhesion/proliferation and IL-8 secretion and a decrease in IL-12 secretion. The LED therapy resulted in a transient increase in the secretion of NO and cytokines IL-1, IL-12, and IL-6 in keratinocytes. The use of magneto-LED therapy resulted in an increase in keratinocyte adhesion/proliferation, the secretion of cytokines IL-6 and IL-8, and NO with a simultaneous decrease in MMP-9 secretion. The results of our studies showed that the action of an LFMF with low-induction and LED light on keratinocytes can modulate the biological activity of keratinocytes towards improving the skin healing process.

Adjuvant effect of antimicrobial photodynamic therapy (aPDT) in the treatment of diabetic foot ulcers: A case series

This study aimed to evaluate the clinical evolution of patients with diabetic foot ulcer treated with antimicrobial photodynamic therapy (aPDT) using the Bates-Jensen (BJ) scale. A total of 21 patients were monitored, with an average age of 58 years. Patients underwent the standard treatment protocol of the institution, supplemented with aPDT utilizing 0.01% methylene blue (MB) and laser irradiation (660 nm, 100 mW, 6 J per point). Following aPDT, the lesions were protected with hydrofiber dressings containing silver. The Bates-Jensen Scale was employed at pre-treatment and post-aPDT sessions to assess lesion progression. The results demonstrated a significant difference between pre- and post-treatment values in the overall BJ score. The use of MB in aPDT proved to be an effective, safe, well-tolerated treatment with high patient adherence and the potential for implementation in the care of diabetic foot conditions.

Effects of photodynamic therapy in patients with infected skin ulcers: A meta-analysis

The purpose of the meta-analysis was to evaluate and compare the photodynamic therapy's effectiveness in treating infected skin wounds. The results of this meta-analysis were analysed, and the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) were calculated using dichotomous or contentious random- or fixed-effect models. For the current meta-analysis, 6 examinations spanning from 2013 to 2021 were included, encompassing 154 patients with infected skin wounds were the used studies' starting point. Photodynamic therapy had a significantly lower wound ulcer size (MD, -4.42; 95% CI, -7.56--1.28, p = 0.006), better tissue repair (MD, -8.62; 95% CI, -16.76--0.48, p = 0.04) and lower microbial cell viability (OR, 0.13; 95% CI, 0.04-0.42, p < 0.001) compared with red light exposure in subjects with infected skin wounds. The examined data revealed that photodynamic therapy had a significantly lower wound ulcer size, better tissue repair and lower microbial cell viability compared with red light exposure in subjects with infected skin wounds. However, given that all examinations had a small sample size, consideration should be given to their values.

Photodynamic therapy for treating infected skin wounds: A systematic review and meta-analysis from randomized clinical trials

BACKGROUND

Infected skin wounds represent a public health problem that effects 20 million people worldwide. Photodynamic therapy (PDT) is a treatment option with excellent results against several infections.

OBJECTIVE

This study aimed to perform a systematic review and meta-analysis on PDT efficacy for treating infected wounds based on randomized clinical trials (RCTs).

METHODS

PubMed, Scopus, Web of Science, SciELO, and the Cochrane library were searched. The Delphi List criteria and the Revised Cochrane risk-of-bias (Rob 2) were used for evaluating the quality of clinical trials. Meta-analyses were performed with the random-effect model. The odds ratio was the effect measure for binary outcomes, while the standard mean difference was used for continuous outcomes. The trim-and-fill method was used to detect small-study effects. The quality of evidence was verified for each outcome.

RESULTS

Only four out of 573 articles were selected for the qualitative and quantitative analyses. The most frequent cause of infected wounds was impaired venous circulation (75%). All studies used red LED light. PDT reduced healing time and improved the healing process and wound oxygenation. Patients treated with PDT showed 15% to 17% (p = 0.0003/ I²=0%) lower microbial cell viability in the wound and a significantly smaller wound size (0.72 cm²/p = 0.0187/I²=0%) than patients treated with placebo or red-light exposure. There was a high level of evidence for each meta-analysis outcome.

CONCLUSION

PDT can be an excellent alternative treatment for infected skin wounds, though larger trials are needed.

The photosensitizer-based therapies enhance the repairing of skin wounds

Wound repair remains a clinical challenge and bacterial infection is a common complication that may significantly delay healing. Therefore, proper and effective wound management is essential. The photosensitizer-based therapies mainly stimulate the photosensitizer to generate reactive oxygen species through appropriate excitation source irradiation, thereby killing pathogenic microorganisms. Moreover, they initiate local immune responses by inducing the recruitment of immune cells as well as the production of proinflammatory cytokines. In addition, these therapies can stimulate the proliferation, migration and differentiation of skin resident cells, and improve the deposition of extracellular matrix; subsequently, they promote the re-epithelialization, angiogenesis, and tissue remodeling. Studies in multiple animal models and human skin wounds have proved that the superior sterilization property and biological effects of photosensitizer-based therapies during different stages of wound repair. In this review, we summarize the recent advances in photosensitizer-based therapies for enhancing tissue regeneration, and suggest more effective therapeutics for patients with skin wounds.