Photobiomodulation Therapy: A New Light in the Treatment of Systemic Sclerosis Skin Ulcers

Dose-response and efficacy of 904 nm photobiomodulation on diabetic foot ulcers healing: a randomized controlled trial

PURPOSE

This study aimed to examine the impact of a 904 nm photobiomodulation (PBM) on diabetic ulcers using varying dosages.

METHODS

The study was a randomized, double-blind, placebo-controlled clinical trial that compared treatments using PBM (GaAs 904 nm 30w) with three different energy densities (4 J/cm2; 8 J/cm2; 10 J/cm2) in the healing process of non-infected diabetic foot ulcers. Eighty volunteers (48.75% female; 58.5 ± 11.1 years) were randomized into three intervention groups treated with PBM and one control group (PBM placebo). Volunteers performed up 20 interventions with PBM, either placebo or actual, in conjunction with conventional therapy, which involved dressing the wound with Helianthus annuus vegetable oil. The primary variable was the ulcer size reduction rate.

RESULTS

GaAs 904 nm PBM yielded a clinically and significant ulcer size rate reduction of diabetic foot ulcers, independently of energy density range (p < 0.05). However, 10 J/cm² had 60% of completely healed ulcers and the highest proportion of patients reaching 50% of ulcer reduction rate after 5 weeks of treatment. In addition, only 10 J/cm² showed a significant difference between control group after a 10-week follow-up (p < 0.05).

CONCLUSION

GaAs 904 nm PBM was effective in treating diabetic foot ulcers in this study and a dosage of 10 J/cm², after a 10-week follow-up, proved to be the most effective compared to the other groups.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04246814.

Non-surgical local treatments of digital ulcers in systemic sclerosis: a systematic literature review

INTRODUCTION

Digital ulcers (DUs) are difficult to treat in patients with systemic sclerosis (SSc) and systemic (i.e., pharmacological) therapy is currently considered the 'standard of care'. Our aim was to examine the safety and efficacy of local, non-surgical treatment for SSc-DUs.

METHODS

A systematic literature review (SLR) of original research articles up to August, 29 2022 was performed according to the PICO framework. References were independently screened by two reviewers and risk of bias was assed using validated tools. Due to study heterogeneity narrative summaries are used to present data.

RESULTS

Among 899 retrieved references, 14 articles were included (2 randomised trials (RTs), and 12 observational (OBS) studies). The most frequently studied procedure (5 studies) was botulin A toxin (hand or single finger) injection with a reported healing rate (HR) of 71%-100%. Amniotic and hydrocolloid membranes were examined in one study each and associated with a good HR. Tadalafil 2% cream was studied in a single study with a reduction in the number of DUs. Vitamin E gel was associated with a reduction in ulcer healing time. Low-level light therapy, hydrodissection and corticosteroid injection, extracorporeal shock wave (ESW) and photobiomodulation were evaluated in a single study each and showed a positive trend. Dimethyl sulfoxide was associated with significant local toxicity.

CONCLUSIONS

A range of non-surgical, local treatments for SSc-DUs have been explored and showed efficacy to some extent. We have identified methodological flaws that should be avoided in the design of future studies to explore locally-acting treatments for SSc-DUs.

Ear keloids: An innovative 3-steps combined treatment

INTRODUCTION

An excessive proliferation of fibroblasts and collagen synthesis after an injury may lead to a benign fibrous tumor, known as keloid, which does not regress spontaneously. Earlobes are a very frequent site of onset, since after a trauma (i.e., piercing) keloids may develop either on the helix and on the anterior or posterior lobe, from a few months up to several years after the injury.

OBJECTIVES

To report the effectiveness of a combined protocol of CO2 laser + Dye laser + a portable Blue LED Light medical device for Photobiomodulation Therapy (EmoLED®).

METHODS

Fifty-two patients with a total of 56 ear keloids have been treated in the same session with a single CO2 laser procedure + a pulsed Dye laser procedure with an adjunctive EmoLED® procedure for 3 up to 6 min. A monthly follow-up has been performed with an adjunctive EmoLED® session in case of signs of inflammation.

RESULTS

Among 56 treated keloids, 89.3% of them (50/56) did not recur during a follow-up period (from 6 up to 24 months, mean 16.3 months) while six keloids recurred (6/56, 10.7%) with mild thickening of the scar, thus requiring further treatments.

CONCLUSIONS

Even if an excellent outcome obtained by the synergistic effect of combined laser treatments has already been described (i.e., CO2 laser + Dye Laser), the present study showed the adjuvant procedure with EmoLED® can reduce significantly the risk of keloids recurrences.

Photobiomodulation at 660 nm Stimulates In Vitro Diabetic Wound Healing via the Ras/MAPK Pathway

Diabetic foot ulcers (DFUs) are open chronic wounds that affect diabetic patients due to hyperglycaemia. DFUs are known for their poor response to treatment and frequently require amputation, which may result in premature death. The present study evaluated the effect of photobiomodulation (PBM) at 660 nm on wound healing via activation of Ras/MAPK signalling in diabetic wounded cells in vitro. This study used four human skin fibroblast cell (WS1) models, namely normal (N), wounded (W), diabetic (D), and diabetic wounded (DW). Cells were irradiated at 660 nm with 5 J/cm2. Non-irradiated cells (0 J/cm2) served as controls. Cells were incubated for 24 and 48 h post-irradiation, and the effect of PBM on cellular morphology and migration rate, viability, and proliferation was assessed. Basic fibroblast growth factor (bFGF), its phosphorylated (activated) receptor FGFR, and phosphorylated target proteins (Ras, MEK1/2 and MAPK) were determined by enzyme-linked immunosorbent assay (ELISA) and Western blotting; nuclear translocation of p-MAPK was determined by immunofluorescence. PBM resulted in an increase in bFGF and a subsequent increase in FGFR activation. There was also an increase in downstream proteins, p-Ras, p-MEK1/2 and p-MAPK. PBM at 660 nm led to increased viability, proliferation, and migration as a result of increased bFGF and subsequent activation of the Ras/MAPK signalling pathway. Therefore, this study can conclude that PBM at 660 nm stimulates in vitro diabetic wound healing via the bFGF-activated Ras/MAPK pathway.

Photobiomodulation with Blue Light on Wound Healing: A Scoping Review

BACKGROUND

Photobiomodulation consists of inducing healing by irradiating light. This scoping review investigates the effect of blue light on the healing process.

METHODS

The MEDLINE, Web of Science, Scopus, and CINAHL databases were searched. Two reviewers independently examined the search results and extracted data from the included studies. A descriptive analysis was performed.

RESULTS

Twenty-two articles were included. Studies were categorized as in vitro/mixed, preclinical, and clinical. The power density used was 10-680 mW/cm² in most of the in vitro/preclinical studies, the irradiation time ranged from 5 s to 10 min, and different wavelengths and energy densities were used. In clinical studies, the wavelength ranged from 405 to 470 nm, and the energy density varied from 1.5 to 30 J/cm².

CONCLUSIONS

A low energy density (<20 J/cm²) was able to stimulate the different cell types and proteins involved in healing, while a high energy density, 20.6-50 J/cm², significantly reduced cell proliferation, migration, and metabolism. There is a great variety of device parameters among studies, and this makes it difficult to conclude what the best technical specifications are. Thus, further studies should be performed in order to define the appropriate parameters of light to be used.

Highlighting nuances of blue light phototherapy: Mechanisms and safety considerations

The efficacy of blue light therapy in dermatology relies on numerous clinical studies. The safety remains a topic of controversy, where potentially deleterious effects were derived from in vitro rather than in vivo experiments. The objectives of this work were (1) to highlight the nuances behind "colors" of blue light, light propagation in tissue and the plurality of modes of action; and (2) to rigorously analyze studies on humans reporting both clinical and histological data from skin biopsies with focus on DNA damage, proliferation, apoptosis, oxidative stress, impact on collagen, elastin, immune cells, and pigmentation. We conclude that blue light therapy is safe for human skin. It induces intriguing skin pigmentation, in part mediated by photoreceptor Opsin-3, which might have a photoprotective effect against ultraviolet irradiation. Future research needs to unravel photochemical reactions and the most effective and safe parameters of blue light in dermatology.

Low-Dose Blue Light (420 nm) Reduces Metabolic Activity and Inhibits Proliferation of Human Dermal Fibroblasts

Hypertrophic scarring in burn wounds is caused by overactive fibroblasts and myofibroblasts. Blue light reveals wavelength- and dose-dependent antibacterial and antiproliferative effects and may serve as a therapeutic option against wound infection and fibrotic conditions. Therefore, we evaluated in this study the effects of single and multiple irradiations with blue light at 420 nm (BL₄₂₀) on the intracellular ATP concentration, and on the viability and proliferation of the human skin fibroblast (HDFs). In addition, possible BL₄₂₀-induced effects on the catalase expression and differentiation were assessed by immunocytochemical staining and western blot analyses. Furthermore, we used RNA-seq analyses to identify BL₄₂₀-affected genes. We found that BL₄₂₀ induced toxicity in HDFs (up to 83%; 180 J/cm²). A low dose of 20 J/cm² reduced the ATP concentration by ~50%. Multiple irradiations (4 × 20 J/cm²) inhibited proliferation without visible toxicity and reduced catalase protein expression by ~37% without affecting differentiation. The expression of about 300 genes was significantly altered. Many downregulated genes have functions in cell division/mitosis. BL₄₂₀ can strongly influence the fibroblast physiology and has potential in wound therapy. However, it is important to consider the possible toxic and antiproliferative effects, which could potentially lead to impaired wound healing and reduced scar breaking strength.

Recognition of Melanocytes in Immuno-Neuroendocrinology and Circadian Rhythms: Beyond the Conventional Melanin Synthesis

Melanocytes produce melanin to protect the skin from UV-B radiation. Notwithstanding, the spectrum of their functions extends far beyond their well-known role as melanin production factories. Melanocytes have been considered as sensory and computational cells. The neurotransmitters, neuropeptides, and other hormones produced by melanocytes make them part of the skin’s well-orchestrated and complex neuroendocrine network, counteracting environmental stressors. Melanocytes can also actively mediate the epidermal immune response. Melanocytes are equipped with ectopic sensory systems similar to the eye and nose and can sense light and odor. The ubiquitous inner circadian rhythm controls the body’s basic physiological processes. Light not only affects skin photoaging, but also regulates inner circadian rhythms and communicates with the local neuroendocrine system. Do melanocytes “see” light and play a unique role in photoentrainment of the local circadian clock system? Why, then, are melanocytes responsible for so many mysterious functions? Do these complex functional devices work to maintain homeostasis locally and throughout the body? In addition, melanocytes have also been shown to be localized in internal sites such as the inner ear, brain, and heart, locations not stimulated by sunlight. Thus, what can the observation of extracutaneous melanocytes tell us about the “secret identity” of melanocytes? While the answers to some of these intriguing questions remain to be discovered, here we summarize and weave a thread around available data to explore the established and potential roles of melanocytes in the biological communication of skin and systemic homeostasis, and elaborate on important open issues and propose ways forward.