Comparison of blue laser and red light-emitting diode-mediated aminolevulinic acid-based photodynamic therapy for moderate and severe acne vulgaris: A prospective, split-face, nonrandomized controlled study.

BACKGROUND: Acne is a chronic inflammatory skin disease. Photodynamic therapy (PDT) is a highly effective and safe drug-device combination treatment, typically using red and blue light. However, direct comparisons of aminolevulinic acid (ALA)-based PDT using these two light sources are lacking. Therefore, we compared the efficacy and adverse effects of ALA-based 450 nm blue laser-mediated PDT (BL-PDT) and 630 ± 10 nm red light-emitting diode-mediated PDT (RL-PDT) in the treatment of moderate-to-severe acne vulgaris, including analyses of different lesion types. METHODS: Sixteen patients with moderate-to-severe acne vulgaris were recruited. All patients underwent BL-PDT on the left side of the face and RL-PDT on the right side. Treatments were administered thrice at 2-week intervals, and follow-up continued for 2 weeks after the final treatment. The average rates of improvement in inflammatory and non-inflammatory acne lesions, IGA (Investigator's Global Assessment) scales, and IGA success rates were calculated. In addition, adverse effects during and after each treatment were recorded. RESULTS: At the 2-week follow-up after the final treatment, the average rates of improvement in total acne, inflammatory, and non-inflammatory lesions were 48.0 %, 63.0 %, and 30.0 % in the BL-PDT group and 42.2 %, 58.1 %, and 27.5 % in the RL-PDT group, respectively. The IGA scores for the two groups decreased by 1.8 and 1.7 points, respectively, and the IGA success rate was 53.3 % in both groups. There were no significant differences between the BL-PDT and RL-PDT groups in any measure of effectiveness. However, the BL-PDT group exhibited more severe adverse effects, especially pain and hyperpigmentation. CONCLUSIONS: BL-PDT and RL-PDT have similar efficacies in moderate-to-severe acne vulgaris and are particularly effective for inflammatory acne lesions. RL-PDT benefits from milder adverse effects than those of BL-PDT.

The order of green and red LEDs irradiation affects the neural differentiation of human umbilical cord matrix-derived mesenchymal cells.

Different wavelengths emitted from light-emitting diodes (LEDs) are known as an influential factor in proliferation and differentiation of various cell types. Since human umbilical cord matrix-derived mesenchymal cells (hUCMs) are ideal tools for human regenerative medicine clinical trials and stem cell researches, in the present study we investigated the neurogenesis effects of single and intermittent green and red LED irradiation on hUCM cells. Exposure of hUCMs to single and intermittent green (530 nm, 1.59 J/cm2) and red (630 nm, 0.318 J/cm2) lights significantly increased the expression of specific genes including nestin, ß-tubulin III and Olig2. Additionally, immunocytochemical analysis confirmed the expression of specific neural-related proteins including nestin, ß-tubulin III, Olig2 and GFAP. Also, alternating exposure of hUCM cells to green and red lights increased the expression of some neural markers more than either light alone. Further research are required to develop the application of LED irradiation as a useful tool for therapeutic purposes including neural repair and regeneration.

Effects of red-light irradiation and melatonininjection on the antioxidant capacity and occurrence of apoptosis in abalones (Haliotis discus hannai) subjected to thermal stress.

High ocean temperatures caused by global warming induce oxidative stress in aquatic organisms. Melatonin treatment and irradiation using red light-emitting diodes (LEDs) have been reported to reduce oxidative stress in a few aquatic organisms. However, the effects of red LED irradiation and melatonin injection on the antioxidant capacity and degree of apoptosis in abalones, which are nocturnal organisms, have not yet been reported. In this study, we compared the expression levels of antioxidant enzymes, total antioxidant capacity, and the degree of apoptosis in abalones subjected to red LED irradiation and melatonin treatment. The results revealed that at high water temperatures (25 °C), the mRNA expression levels of the superoxide dismutase (SOD) and glutathione peroxidase (GPx) genes and the antioxidant activity of SOD decreased in abalones in the red-LED irradiated and melatonin-treated groups compared with those in abalones in the control group. Although high water temperatures induced DNA damage in the abalone samples, the degree of apoptosis was lower in the red-LED irradiated and melatonin-treated groups than in the control group. Overall, the abalones in the melatonin-treated and red-LED irradiated groups showed reduced oxidative stress and increased antioxidant enzyme levels under thermal stress compared with those in the control group. Therefore, red LED irradiation is a promising alternative to melatonin treatment, which is difficult to administer continuously for a long time, for protecting abalones from oxidative stress.

Protective Effect of Red Light-Emitting Diode against UV-B Radiation-Induced Skin Damage in SKH:HR-2 Hairless Mice.

In this in vivo study on hairless mice, we examined the effects of light-emitting diode (LED) treatment applied prior to ultraviolet B (UVB) irradiation. We found that pre-treating with LED improved skin morphological and histopathological conditions compared to those only exposed to UVB irradiation. In our study, histological evaluation of collagen and elastic fibers after LED treatment prior to UVB irradiation showed that this pretreatment significantly enhanced the quality of fibers, which were otherwise poor in density and irregularly arranged due to UV exposure alone. This suggests that LED treatment promotes collagen and elastin production, leading to improved skin properties. Additionally, we observed an increase in Claudin-1 expression and a reduction in nuclear factor-erythroid 2-related factor 2 (Nrf-2) and heme-oxygenase 1 (HO-1) expression within the LED-treated skin tissues, suggesting that LED therapy may modulate key skin barrier proteins and oxidative stress markers. These results demonstrate that pretreatment with LED light can enhance the skin's resistance to UVB-induced damage by modulating gene regulation associated with skin protection. Further investigations are needed to explore the broader biological effects of LED therapy on other tissues such as blood vessels. This study underscores the potential of LED therapy as a non-invasive approach to enhance skin repair and counteract the effects of photoaging caused by UV exposure.

Red light-emitting diode therapy minimizes the functional deleterious effects of the antiretroviral ritonavir on osteoblasts in vitro.

PURPOSE: Long-term human immunodeficiency virus (HIV)-infected patients are considered at higher risk for osteoporosis. Among the various causes that lead these patients to lower bone health, there is the use of antiretroviral drugs (ARVs), especially protease inhibitors (PI), such as ritonavir (RTV). In this context, emerge the potential benefits of LED therapy, whose effects on bone cells are currently being extensively studied, showing a modulation in cell differentiation. However, it remains unclear if photobiostimulation might interfere with RTV effects on osteoblast differentiation. METHODS: In the present study, we investigated the effects of red LED (625 nm) irradiation (15 mW/cm2, 0.2 J/cm2, and 8 mW/cm2, 0.12 J/cm2) on osteoblast cell line MC3T3-E1 treated with RTV (2.5, 5, and 10 µg/mL). RESULTS: Our results indicated that red LED irradiation was able to reverse, or at least minimize, the deleterious effects of RTV on the osteoblasts. Neither the ARV treatments 5 and 10 µg/mL (104.4% and 95.01%) nor the LED protocols (100.3% and 105.7%) statistically altered cell viability, assessed by the MTT assay. Also, the alkaline phosphatase activity and mineralization showed a decrease in osteoblast activity followed by ARV exposure (39.3-73%), which was attenuated by LED in more than 70% with statistical significance (p < 0.05). CONCLUSION: In conclusion, photobiostimulation with red LED at 625 nm was associated with improved beneficial biological effects as a potential inducer of osteogenic activity on RTV-affected cells. This is the first study that investigated the benefits of red LED irradiation over ARV-treated in vitro osteoblasts.

Narrow Band Ultraviolet B Versus Red Light-Emitting Diodes in the Treatment of Facial Acne Vulgaris: A Randomized Controlled Trial.

Background: One of the most common dermatological conditions affecting most teenagers is acne. Phototherapy was described as a therapeutic modality with low-side effects of acne vulgaris (AV). Hence, we examined the effects of narrow band ultraviolet B (NBUVB) versus red light-emitting diodes (LEDs) on facial AV. Methods: Forty-five subjects suffering from facial AV mild to a moderate degree were randomly assigned into three groups, 15 subjects within every group. Group A was equipped to NBUVB with 311-313 nm and an initial dose of 250 mJ/cm2, thrice a week for 8 weeks, Group B was equipped red LED with wavelengths 633 ± 6 nm and power density of 80 mW/cm2, thrice a week for 8 weeks, whereas group C had received the only erythromycin as a control group. Outcome measures included measurement of acne lesion count and degree of severity. Measures at three-time intervals were assessed: baseline, 4 weeks (post I), and 8 weeks (post II). Results: Acne numeral findings revealed a significant variance among groups A, B, and C in favor of group A (p < 0.001). Notable improvements were observed across all three groups (p < 0.001). The degree of adjustment effects indicated a greater increase in group A in comparison with group B (p < 0.01), whereas no statistical variance was detected between group B and group C (p > 0.05). Conclusions: Both NBUVB and red LED were effective in acne treatment; NBUVB, however, revealed a highly efficient treatment than red LED in decreasing the acne lesions count and the improved degree of AV severity as measured by the global investigator's assessment scale. Clinical Trial Registration No. NCT04254601.

Development and Characterization of An Injury-free Model of Functional Pain in Rats by Exposure to Red Light.

We report the development and characterization of a novel, injury-free rat model in which nociceptive sensitization after red light is observed in multiple body areas reminiscent of widespread pain in functional pain syndromes. Rats were exposed to red light-emitting diodes (RLED) (LEDs, 660 nm) at an intensity of 50 Lux for 8 hours daily for 5 days resulting in time- and dose-dependent thermal hyperalgesia and mechanical allodynia in both male and female rats. Females showed an earlier onset of mechanical allodynia than males. The pronociceptive effects of RLED were mediated through the visual system. RLED-induced thermal hyperalgesia and mechanical allodynia were reversed with medications commonly used for widespread pain, including gabapentin, tricyclic antidepressants, serotonin/norepinephrine reuptake inhibitors, and nonsteroidal anti-inflammatory drugs. Acetaminophen failed to reverse the RLED induced hypersensitivity. The hyperalgesic effects of RLED were blocked when bicuculline, a gamma-aminobutyric acid-A receptor antagonist, was administered into the rostral ventromedial medulla, suggesting a role for increased descending facilitation in the pain pathway. Key experiments were subjected to a replication study with randomization, investigator blinding, inclusion of all data, and high levels of statistical rigor. RLED-induced thermal hyperalgesia and mechanical allodynia without injury offers a novel injury-free rodent model useful for the study of functional pain syndromes with widespread pain. RLED exposure also emphasizes the different biological effects of different colors of light exposure. PERSPECTIVE: This study demonstrates the effect of light exposure on nociceptive thresholds. These biological effects of red LED add evidence to the emerging understanding of the biological effects of light of different colors in animals and humans. Understanding the underlying biology of red light-induced widespread pain may offer insights into functional pain states.

Low-level red LED light inhibits hyperkeratinization and inflammation induced by unsaturated fatty acid in an in vitro model mimicking acne.

BACKGROUND AND OBJECTIVE: Acne vulgaris is a chronic inflammatory disease of the pilosebaceous units (PSU), associated with increased sebum production, abnormal follicular keratinization (hyperkeratinization), follicular overgrowth of Propionibacterium acnes (P. acnes), and increased inflammatory mediator release. Light therapy has attracted medical interests as a safe alternative treatment for acne. Both blue and red light therapies at high doses >10 J/cm2 have demonstrated marked effects on inflammatory acne lesions. However, few studies have investigated the effects of lower doses of light. The aim of this study is to investigate the biological effects of lower doses of red light at 0.2-1.2 J/cm2 for acne using an in vitro model previously developed to mimic the inflammation and hyperkeratinization observed clinically in acne. MATERIALS AND METHODS: Human epidermal equivalents were topically exposed to an unsaturated fatty acid, oleic acid (OA), followed by red light-emitting diode (LED) light treatments (light-plus-OA treatments). Endpoints evaluated included the proinflammatory cytokine IL-1α, epidermal barrier integrity, as measured by transepithelial electrical resistance (TEER), and stratum corneum (SC) thickness to monitor hyperkeratinization. RESULTS: OA-induced IL-1α release was significantly (P < 0.05) reduced following red LED light at 0.2, 0.5, and 1.2 J/cm2 , from 266 ± 11 pg/ml of no-light-plus-OA-treated (OA treatment without light) controls to 216 ± 9, 231 ± 8, and 212 ± 7 pg/ml, respectively. Histological examination showed that SC thickening following OA treatment was reduced from 43% of total epidermis for no-light-plus-OA treatment to 37% and 38% of total epidermis following 0.5 and 1.1 J/cm2 red light plus OA treatment, respectively (P < 0.05). Moreover, 1.1 J/cm2 red-light-plus-OA treatment improved OA-induced TEER changes from 29% of baseline for no-light-plus-OA treatment, to 36% of baseline. CONCLUSION: Low level red LED light therapy could provide beneficial effects of anti-inflammation, normalizing pilosebaceous hyperkeratinization, and improving barrier impairment in Acne vulgaris. Lasers Surg. Med. 50:158-165, 2018. © 2017 Wiley Periodicals, Inc.

Photodynamic inactivation of pathogenic species Pseudomonas aeruginosa and Candida albicans with lutetium (III) acetate phthalocyanines and specific light irradiation.

Photodynamic inactivation (PDI) is a light-associated therapeutic approach suitable for treatment of local acute infections. The method is based on specific light-activated compound which by specific irradiation and in the presence of molecular oxygen produced molecular singlet oxygen and other reactive oxygen species, all toxic for pathogenic microbial cells. The study presents photodynamic impact of two recently synthesized water-soluble cationic lutetium (III) acetate phthalocyanines (LuPc-5 and LuPc-6) towards two pathogenic strains, namely, the Gram-negative bacterium Pseudomonas aeruginosa and a fungus Candida albicans. The photodynamic effect was evaluated for the cells in suspensions and organized in 48-h developed biofilms. The relatively high levels of uptakes of LuPc-5 and LuPc-6 were determined for fungal cells compared to bacterial cells. The penetration depths and distribution of both LuPcs into microbial biofilms were investigated by means of confocal fluorescence microscopy. The photoinactivation efficiency was studied for a wide concentration range (0.85-30 µM) of LuPc-5 and LuPc-6 at a light dose of 50 J cm-2 from red light-emitting diode (LED; 665 nm). The PDI study on microbial biofilms showed incomplete photoinactivation (<3 logs) for the used gentle drug-light protocol.

Bactericidal effects of a high-power, red light-emitting diode on two periodontopathic bacteria in antimicrobial photodynamic therapy in vitro.

AIM: Light-emitting diodes have been investigated as new light activators for photodynamic therapy. We investigated the bactericidal effects of high-power, red light-emitting diodes on two periodontopathic bacteria in vitro. METHODS: A light-emitting diode (intensity: 1100 mW/cm(2) , peak wavelength: 650 nm) was used to irradiate a bacterial solution for either 10 or 20 s. Bacterial solutions (Porphyromonas gingivalis or Aggregatibacter actinomycetemcomitans) at a concentration of 2.5 × 10(6) c.f.u./mL were mixed with an equal volume of either methylene blue or toluidine blue O (0-20 µg/mL) and added to titer plate wells. The plate wells were irradiated with red light-emitting diode light from a distance of 22 or 40 mm. The contents were diluted, and 50 µL was smeared onto blood agar plates. After 1 week of culturing, bacterial c.f.u. were counted. RESULTS: The light-emitting diode energy density was estimated to be approximately 4 and 8 J/cm(2) after 10 and 20 s of irradiation, respectively. Red light-emitting diode irradiation for 10 s from a distance of 22 mm, combined with methylene blue at concentrations >10 µg/mL, completely killed Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. CONCLUSION: High-power, red light-emitting diode irradiation with a low concentration of dye showed effective bactericidal effects against two periodontopathic bacteria.