Near-Infrared II Photobiomodulation Preconditioning Ameliorates Stroke Injury via Phosphorylation of eNOS.

BACKGROUND: The current management of patients with stroke with intravenous thrombolysis and endovascular thrombectomy is effective only when it is timely performed on an appropriately selected but minor fraction of patients. The development of novel adjunctive therapy is highly desired to reduce morbidity and mortality with stroke. Since endothelial dysfunction is implicated in the pathogenesis of stroke and is featured with suppressed endothelial nitric oxide synthase (eNOS) with concomitant nitric oxide deficiency, restoring endothelial nitric oxide represents a promising approach to treating stroke injury. METHODS: This is a preclinical proof-of-concept study to determine the therapeutic effect of transcranial treatment with a low-power near-infrared laser in a mouse model of ischemic stroke. The laser treatment was performed before the middle cerebral artery occlusion with a filament. To determine the involvement of eNOS phosphorylation, unphosphorylatable eNOS S1176A knock-in mice were used. Each measurement was analyzed by a 2-way ANOVA to assess the effect of the treatment on cerebral blood flow with laser Doppler flowmetry, eNOS phosphorylation by immunoblot analysis, and stroke outcomes by infarct volumes and neurological deficits. RESULTS: Pretreatment with a 1064-nm laser at an irradiance of 50 mW/cm2 improved cerebral blood flow, eNOS phosphorylation, and stroke outcomes. CONCLUSIONS: Near-infrared II photobiomodulation could offer a noninvasive and low-risk adjunctive therapy for stroke injury. This new modality using a physical parameter merits further consideration to develop innovative therapies to prevent and treat a wide array of cardiovascular diseases.

Photobiomodulation in the infrared spectrum reverses the expansion of circulating natural killer cells and brain microglial activation in Sanfilippo mice.

Sanfilippo syndrome results from inherited mutations in genes encoding lysosomal enzymes that catabolise heparan sulfate (HS), leading to early childhood-onset neurodegeneration. This study explores the therapeutic potential of photobiomodulation (PBM), which is neuroprotective and anti-inflammatory in several neurodegenerative diseases; it is also safe and PBM devices are readily available. We investigated the effects of 10-14 days transcranial PBM at 670 nm (2 or 4 J/cm2/day) or 904 nm (4 J/cm2/day) in young (3 weeks) and older (15 weeks) Sanfilippo or mucopolysaccharidosis type IIIA (MPS IIIA) mice. Although we found no PBM-induced changes in HS accumulation, astrocyte activation, CD206 (an anti-inflammatory marker) and BDNF expression in the brains of Sanfilippo mice, there was a near-normalisation of microglial activation in older MPS IIIA mice by 904 nm PBM, with decreased IBA1 expression and a return of their morphology towards a resting state. Immune cell immunophenotyping of peripheral blood with mass cytometry revealed increased pro-inflammatory signalling through pSTAT1 and p-p38 in NK and T cells in young but not older MPS IIIA mice (5 weeks of age), and expansion of NK, B and CD8+ T cells in older affected mice (17 weeks of age), highlighting the importance of innate and adaptive lymphocytes in Sanfilippo syndrome. Notably, 670 and 904 nm PBM both reversed the Sanfilippo-induced increase in pSTAT1 and p-p38 expression in multiple leukocyte populations in young mice, while 904 nm reversed the increase in NK cells in older mice. In conclusion, this is the first study to demonstrate the beneficial effects of PBM in Sanfilippo mice. The distinct reduction in microglial activation and NK cell pro-inflammatory signalling and number suggests PBM may alleviate neuroinflammation and lymphocyte activation, encouraging further investigation of PBM as a standalone, or complementary therapy in Sanfilippo syndrome.

Photobiomodulation transiently increases the spontaneous firing in the superficial layer of the rat spinal dorsal horn.

The therapeutic benefits of photobiomodulation (PBM) in pain management, although well documented, are accompanied by concerns about potential risks, including pain, particularly at higher laser intensities. This study investigated the effects of laser intensity on pain perception using behavioral and electrophysiological evaluations in rats. Our results show that direct laser irradiation of 1000 mW/cm2 to the sciatic nerve transiently increases the frequency of spontaneous firing in the superficial layer without affecting the deep layer of the spinal dorsal horn, and this effect reverses to pre-irradiation levels after irradiation. Interestingly, laser irradiation at 1000 mW/cm2, which led to an increase in spontaneous firing, did not prompt escape behavior. Furthermore, a significant reduction in the time to initiate escape behavior was observed only at 9500 mW/cm2 compared to 15, 510, 1000, and 4300 mW/cm2. This suggests that 1000 mW/cm2, the laser intensity at which an increase in spontaneous firing was observed, corresponds to a stimulus that did not cause pain. It is expected that a detailed understanding of the risks and mechanisms of PBM from a neurophysiological perspective will lead to safer and more effective use of PBM.

Effects of Low-Level Light Therapy on Resting-State Connectivity Following Moderate Traumatic Brain Injury: Secondary Analyses of a Double-blinded Placebo-controlled Study.

Background Low-level light therapy (LLLT) has been shown to modulate recovery in patients with traumatic brain injury (TBI). However, the impact of LLLT on the functional connectivity of the brain when at rest has not been well studied. Purpose To use functional MRI to assess the effect of LLLT on whole-brain resting-state functional connectivity (RSFC) in patients with moderate TBI at acute (within 1 week), subacute (2-3 weeks), and late-subacute (3 months) recovery phases. Materials and Methods This is a secondary analysis of a prospective single-site double-blinded sham-controlled study conducted in patients presenting to the emergency department with moderate TBI from November 2015 to July 2019. Participants were randomized for LLLT and sham treatment. The primary outcome of the study was to assess structural connectivity, and RSFC was collected as the secondary outcome. MRI was used to measure RSFC in 82 brain regions in participants during the three recovery phases. Healthy individuals who did not receive treatment were imaged at a single time point to provide control values. The Pearson correlation coefficient was estimated to assess the connectivity strength for each brain region pair, and estimates of the differences in Fisher z-transformed correlation coefficients (hereafter, z differences) were compared between recovery phases and treatment groups using a linear mixed-effects regression model. These analyses were repeated for all brain region pairs. False discovery rate (FDR)-adjusted P values were computed to account for multiple comparisons. Quantile mixed-effects models were constructed to quantify the association between the Rivermead Postconcussion Symptoms Questionnaire (RPQ) score, recovery phase, and treatment group. Results RSFC was evaluated in 17 LLLT-treated participants (median age, 50 years [IQR, 25-67 years]; nine female), 21 sham-treated participants (median age, 50 years [IQR, 43-59 years]; 11 female), and 23 healthy control participants (median age, 42 years [IQR, 32-54 years]; 13 male). Seven brain region pairs exhibited a greater change in connectivity in LLLT-treated participants than in sham-treated participants between the acute and subacute phases (range of z differences, 0.37 [95% CI: 0.20, 0.53] to 0.45 [95% CI: 0.24, 0.67]; FDR-adjusted P value range, .010-.047). Thirteen different brain region pairs showed an increase in connectivity in sham-treated participants between the subacute and late-subacute phases (range of z differences, 0.17 [95% CI: 0.09, 0.25] to 0.26 [95% CI: 0.14, 0.39]; FDR-adjusted P value range, .020-.047). There was no evidence of a difference in clinical outcomes between LLLT-treated and sham-treated participants (range of differences in medians, -3.54 [95% CI: -12.65, 5.57] to -0.59 [95% CI: -7.31, 8.49]; P value range, .44-.99), as measured according to RPQ scores. Conclusion Despite the small sample size, the change in RSFC from the acute to subacute phases of recovery was greater in LLLT-treated than sham-treated participants, suggesting that acute-phase LLLT may have an impact on resting-state neuronal circuits in the early recovery phase of moderate TBI. ClinicalTrials.gov Identifier: NCT02233413 © RSNA, 2024 Supplemental material is available for this article.

Effects of slit lamp-delivered retinal laser photobiomodulation in a rat model of choroidal neovascularization.

Neovascular age-related macular degeneration, also known as exudative or wet age-related macular degeneration, is the leading cause of blindness in the developed world. Photobiomodulation has the potential to target the up-stream hypoxic and pro-inflammatory drivers of choroidal neovascularization. This study investigated whether photobiomodulation attenuates characteristic pathological features of choroidal neovascularization in a rodent model. Experimental choroidal neovascularization was induced in Brown Norway rats with laser photocoagulation. A custom-designed, slit-lamp-mounted, 670 nm laser was used to administer retinal photobiomodulation every 3 days, beginning 6 days prior to choroidal neovascularization induction and continuing until the animals were killed 14 days later. The effect of photobiomodulation on the size of choroidal neovascular membranes was determined using isolectin-B4 immunohistochemistry and spectral domain-optical coherence tomography. Vascular leakage was determined with fluorescein angiography. The effect of treatment on levels of vascular endothelial growth factor expression was quantified with enzyme-linked immunosorbent assay. Treatment with photobiomodulation was associated with choroidal neovascular membranes that were smaller, had less fluorescein leakage, and a diminished presence of inflammatory cells as compared to sham eyes. These effects were not associated with a statistically significant difference in the level of vascular endothelial growth factor when compared to sham eyes. The data shown herein indicate that photobiomodulation attenuates pathological features of choroidal neovascularization in a rodent model by mechanisms that may be independent of vascular endothelial growth factor.

Low-Level Laser Therapy for Allergic Rhinitis: A Systematic Review and Meta-Analysis.

INTRODUCTION: Allergic rhinitis (AR) is a common allergic disorder that impairs social and physical functioning as well as quality of life. It is characterized by sneezing, rhinorrhea, congestion, and itching which respond suboptimally to drug therapy. Low-level laser therapy (LLLT) has anti-inflammatory and immunosuppressive properties that have shown promise in some studies. We aimed to systematically review LLLT's effectiveness in treating AR and meta-analyze our findings. METHODS: A systematic search of PubMed, Scopus, and Web of Science was conducted on November 24, 2023. All studies investigating LLLT on AR were included, and a pre-post meta-analysis of nasal symptoms (rhinorrhea, nasal congestion, nasal itching, and sneezing) in the LLLT-treated arm was conducted. Rhinoconjunctivitis quality of life questionnaire (RQLQ) scores before and after LLLT were also meta-analyzed alongside a pairwise meta-analysis of LLLT with placebo, acupuncture, steroids/antihistamines, and ultraviolet lasers. A random-effects model was used with a conservative pre-post correlation of 0.4 and standardized mean difference (SMD) as the effect size. RESULTS: Sixteen studies were included in this review, and we found that nasal symptoms are alleviated post-LLLT in people with AR (SMD: -1.4, 95 CI: [-2.07 to -1.13], p value <0.001). RQLQ scores were also reduced after LLLT (SMD = -0.72, 95 CI: [-0.94 to -0.50], p value <0.001), and very few adverse events were reported. This meta-analysis, however, had significant publication bias and heterogeneity. When compared to a placebo, LLLT did not significantly improve nasal symptoms (SMD: -0.69, p value = 0.167), which might mean the post-LLLT nasal symptom alleviation is due to a placebo effect. Comparisons to other treatment modalities were too few to deduce anything meaningful, although it does appear that LLLT is less effective than UV lasers. CONCLUSION: LLLT is most likely effective at alleviating nasal symptomology and has a low likelihood of adverse event incidence, yet more high-quality studies with larger sample sizes are needed to compare LLLT to a placebo to ensure its superiority to the placebo effect, as well as non-inferiority clinical trials to compare it to standard treatments.

Implementation of a light therapy team to administer photobiomodulation therapy: A standardized protocol to prevent and treat oral mucositis in the pediatric hematopoietic stem cell transplant population.

BACKGROUND: Oral mucositis (OM) is a painful and common complication of hematopoietic stem cell transplant (HSCT). The Children's Oncology Group recently published guidelines recommending photobiomodulation (PBM) for preventing and treating OM in pediatric HSCT patients. However, this is a rarely used intervention in pediatric hospitals. PROCEDURE: Patients undergoing allogeneic HSCT, or autologous HSCT for a neuroblastoma diagnosis, had PBM administered from the first day of conditioning to transplant Day +20. We successfully developed a standardized treatment protocol and workflow to ensure consistent and uniform delivery of PBM. In addition, clinical patient data were compared before and after PBM implementation. RESULTS: The administration of PBM at our center was feasible, but required dedicated staff. A registered nurse (RN) was determined to be the best fit to deliver PBM. Sixty-two patients received PBM from October 2022 to September 2023; patients from 2021 before PBM implementation were used for comparison. Patients receiving PBM were more likely (p = .03) to engage in teeth brushing (56/62 = 90%) compared to baseline (61/81 = 75%). Mean days of OM decreased from 11.3 to 9 days; patients who received PBM were less likely (p < .001) to be discharged on total parental nutrition (TPN) (11/62 = 18%) compared to baseline (50/82 = 61%). OM-related supportive care costs (TPN and patient-controlled anesthesia [PCA]) were lower (p = .02) for those who received PBM (median cost = $31,229.87 vs. $37,370.66). CONCLUSION: PBM, as the standard of care in the pediatric HSCT population, is safe, feasible, and well-tolerated. At our center, a dedicated RN was critical to providing standardized treatment and ensuring sustainability.

Photobiomodulation combination therapy as a new insight in neurological disorders: a comprehensive systematic review.

Preclinical and clinical studies have indicated that combining photobiomodulation (PBM) therapy with other therapeutic approaches may influence the treatment process in a variety of disorders. The purpose of this systematic review was to determine whether PBM-combined therapy provides additional benefits over monotherapies in neurologic and neuropsychiatric disorders. In addition, the review describes the most commonly used methods and PBM parameters in these conjunctional approaches.To accomplish this, a systematic search was conducted in Google Scholar, PubMed, and Scopus databases through January 2024. 95 potentially eligible articles on PBM-combined treatment strategies for neurological and neuropsychological disorders were identified, including 29 preclinical studies and 66 clinical trials.According to the findings, seven major categories of studies were identified based on disease type: neuropsychiatric diseases, neurodegenerative diseases, ischemia, nerve injury, pain, paresis, and neuropathy. These studies looked at the effects of laser therapy in combination with other therapies like pharmacotherapies, physical therapies, exercises, stem cells, and experimental materials on neurological disorders in both animal models and humans. The findings suggested that most combination therapies could produce synergistic effects, leading to better outcomes for treating neurologic and psychiatric disorders and relieving symptoms.These findings indicate that the combination of PBM may be a useful adjunct to conventional and experimental treatments for a variety of neurological and psychological disorders.

Might photobiomodulation therapy interfere with the frequency of severe mucositis and oral candidiasis? A retrospective analysis in patients with head and neck carcinoma.

PURPOSE: Considering the tumor in the oral cavity or the oropharynx and nasopharynx region might be an aggravating factor for oral mucositis (OM) manifestation, the present study aimed to evaluate whether the location of the tumor and the use of photobiomodulation therapy (PBMT) might affect the frequency of oral candidiasis (OC) during radiotherapy (RT) and/or chemotherapy (CT) treatments. METHODS: The medial records of seventy-four patients with head and neck cancer treated in a public service from 2016 to 2019 were evaluated. All these patients were submitted to RT in an accumulated dose of 48 to 70 Gy of radiation. Data about OM and OC were collected and presented according to the application of a therapeutic protocol with laser photobiomodulation (PBMT) to control oral mucositis, or not (No-PBM), and the location of tumor (head and neck or oral cavity). In the PBMT group patients, a low-power laser device composed of InGaAlP diode (maximum output power of 86.7 mW, active tip area of 0.1256 cm2, and continuous wavelength of 660 nm), was applied to the lips (three points each), right and left jugal mucosa (three points each), the limit between hard and soft palate (three points), buccal floor/sublingual gland (one point), lateral edge of the tongue (three points on each side), and back of the tongue (six points), three times weekly, for 5 weeks. The dosimetry used in each application was 2 J for 3 s, thus totaling 56 J. The correlation between clinical characteristics such as age, tumor size (T), metastatic lymph node (N), number of RT and CT sessions, candidiasis, and OM were analyzed. RESULTS: Mucositis grades 1 and 2 were the most common among all patients, especially before the 12th radiotherapy session, regardless of the treatment with PBM (p > 0.05). Additionally, no difference in the grade of OM and OC was significantly observed when comparing the two laser therapy groups. OC was more frequent after the 12th radiotherapy session in all groups. Nonetheless, OM and OC had a different correlation regarding to tumor location (head and neck and oral cavity) being PBMT a positive therapy to delay OM. It was observed a positive and statistically significant correlation between tumors at oral cavity and OM, regardless PBMT (R = 0.84, p < 0.05 to PBMT and R = 0.13, p < 0.05 to No-PBM). Otherwise, OC was positively correlated to local metastasis in patients with oral tumors undergoing PBMT (R = 0.84, p < 0.05). CONCLUSION: Patients with oral cavity tumor presented more OM, especially high grades, then patients with tumors in other regions of the head and neck, which seems to be related to the irradiation parameters of radiotherapy and/or with the limitation of conduction of PBMT in tumor areas. OM and OC were not changed by PBMT, although it helped to reduce the incidence of severe cases of OM.

Oral mucositis management with photobiomodulation, Bidens pilosa L. (Asteraceae) and Curcuma longa L. (Zingiberaceae), the FITOPROT herbal medicine, and its influence on inflammatory cytokine levels: a randomized clinical trial.

PURPOSE: This randomized clinical trial aimed to compare the effects of a mucoadhesive formula, containing curcuminoids from Curcuma longa L. and glycerinated extract of Bidens pilosa L. (FITOPROT), associated with photobiomodulation (PBM), and of PBM exclusively, on the incidence of oral mucositis (OM)-induced by radiotherapy (RT) in the head and neck region, and the salivary expression of inflammatory cytokines, in patients with head neck cancer. METHODS: Patients were randomly assigned into two intervention groups-FITOPROT + PBM (n = 25) or PBM (n = 27). PBM protocol comprised a wavelength of 660 nm, 25 mW, 0.25 J/point, and daily irradiation from the first until the last day of RT. FITOPROT was gargled twice a day. All patients underwent a preventive oral care program throughout the study. OM degree, salivary concentration of nitrite, and inflammatory (IL-1, TNFα, IL-6, IL-8, and IL-12p70), and anti-inflammatory (IL-10) cytokines were assessed at baseline, and at the 7th, 14th, 21st, and 30th RT sessions. RESULTS: There were no differences in the OM degree between groups, but the RT dose significantly affected the OM. The RT significantly affected the salivary nitrite, TNFα, IL-1ß, and IL-10 concentrations. CONCLUSION: FITOPROT associated with PBM showed limited effects on preventing the incidence of severe OM compared to PBM alone. However, FITOPROT + PBM may be associated with nitrite and cytokine balance, which may contribute to the occurrence of fewer cases of severe OM. TRIAL REGISTRATION: Brazilian Clinical Trials database (ReBEC; RBR-9vddmr), registered UTN code: U1111-1193-2066, registered in August 8th, 2017.

Enhanced Recovery of Local Anesthesia in Pediatric Patients: The Impact of Photobiomodulation on Reversing Anesthesia Effects.

BACKGROUND The split-mouth study design is used in oral health research and usually consists of 2 treatments randomly assigned to either the right or left side. This split-mouth study aimed to evaluate the efficacy of photobiomodulation on reversal of local anesthesia in 50 children aged 8-10 years. MATERIAL AND METHODS The study was conducted among 50 children: 27 girls and 23 boys, aged 8-10 years (mean age 9.38±1.15 years), who presented 2 carious maxillary permanent molars. One side was randomly assigned to the laser group (50 teeth), and the contralateral side to the control group (50 teeth). At the end of the treatment, photobiomodulation (PBM) was performed in the area of infiltration at 6 points, with 635 nm (25 children) (250 mW, 500 mW/cm², 15J) and 808 nm (25 children) (200 mW, 400 mW/cm², 12J) (SmartM PRO, Lasotronix, Poland). On the contralateral side, the laser's off-mode applicator was used. Anesthetic effect was evaluated by palpation test (soft tissues) and electrical test (dental pulp). RESULTS After 15 minutes, in the laser group the return to normal sensations in the palpation test showed 88% (808 nm) and 68% (635 nm), and only 20% in the control group (P=0.04123). After 45 minutes, all the participants from the PBM group returned to normal sensations (P=0.21458). Dental pulp's excitability threshold was lower for both wavelengths compared to the control group (P=0.000001). CONCLUSIONS The identification of factors accelerating the recovery time to normal function, such as PBM, can be used as important data to eliminate self-injury secondary to local anesthesia (LA) in children.

Efficacy of adjunctive modalities during tooth extraction for the prevention of osteoradionecrosis: A systematic review and meta-analysis.

BACKGROUND: Jaw osteoradionecrosis (ORN) is a complication in patients with previous head and neck radiotherapy. Its incidence increases with dental extractions. Hence, this review aimed to evaluate the efficacy of adjunctive treatment modalities undertaken at the time of extraction in previous head and neck radiotherapy patients in preventing ORN. METHODS: A systematic review was conducted, where studies with data on ORN incidence after extraction with or without adjunctive interventions were included. Meta-analyses were conducted to estimate the pooled prevalence of ORN per intervention and the pooled odds ratio for incidence of ORN between interventions. RESULTS: In total, 1520 patients in 29 studies were included. Interventions identified were hyperbaric oxygen (HBO), pentoxifylline-tocopherol (PENTO), antibiotics (ABX), platelet-rich fibrin and photobiomodulation. The pooled prevalence of ORN for HBO (4.6%), PENTO (3.4%) and ABX (3.8%) was significantly lower than the Control (17.6%). For studies with direct comparisons between groups, HBO had lower but not significant odds of developing ORN than the Control (OR 0.27) and ABX (OR 0.57). CONCLUSIONS: HBO, PENTO and ABX may reduce the incidence of ORN compared to no intervention. Given that all three have similar incidences of ORN, ABX may be the most cost-effective and accessible adjunctive modality.

Efficacy of Repeated Low-Level Red Light (RLRL) therapy on myopia outcomes in children: a systematic review and meta-analysis.

BACKGROUND: Myopia is the most prevalent form of refractive error that has a major negative impact on visual function and causes blurring of vision. We aimed to determine if Repeated Low-Level Red Light (RLRL) treatment is beneficial in treating childhood myopia in terms of axial length (AL), spherical equivalent refraction (SER), and sub foveal choroidal thickness (SFCT). METHODS: This systematic review was performed on RLRL for treatment of myopia in children compared to single vision spectacles (SVS). We employed the search strategy with key terms myopia and low-level light therapy then we searched PubMed, Scopus, Cochrane, and Web of Science databases. The mean differences (MD) were used to evaluate the treatment effects. Heterogeneity was quantified using I2 statistics and explored by sensitivity analysis. RESULTS: Five randomized controlled trials (RCTs) were included in our meta-analysis with a total of 833 patients, 407 in treatment group and 426 in control group. At a 3 month follow up period, pooled studies show a statistical difference in AL between RLRL and SVS group (MD = -0.16; 95% CI [-0.19, -0.12], SER (MD = 0.33; 95% CI [0.27, 0.38]), and SFCT (MD = 43.65; 95% CI [23.72, 45.58]). At a 6 month follow up period, pooled studies show a statistical difference in AL between RLRL and SVS group (MD = -0.21; 95% CI [-0.28, -0.15]), SER (MD = 0.46; 95% CI [0.26, 0.65]), and SFCT (MD = 25.07; 95% CI [18.18, 31.95]). At a 12 month follow up period, pooled studies show a statistical difference in AL between RLRL and SVS group (MD = -0.31; 95% CI [-0.42, -0.19]) and SER (MD = 0.63; 95% CI [0.52, 0.73]). CONCLUSION: This is the first systematic review and meta-analysis investigating only RCTs evidence supporting the efficacy of 650 nm RLRL for myopia control in the short term of 3, 6, and 12 months follow up. The present review revealed the clinical significance of RLRL as a new alternative treatment for myopia control with good user acceptability and no documented functional or structural damage. However, the effect of long-term RLRL treatment and the rebound effect after cessation require further investigations.

A retrospective study of cumulative absolute reduction in axial length after photobiomodulation therapy.

BACKGROUND: To assess the age and timeline distribution of ocular axial length shortening among myopic children treated with photobiomodulation therapy in the real world situations. METHODS: Retrospective study of photobiomodulation therapy in Chinese children aged 4 to 13 years old where axial length measurements were recorded and assessed to determine effectiveness at two age groups (4 ∼ 8 years old group and 9 ∼ 13 years old group). Data was collected from myopic children who received photobiomodulation therapy for 6 ∼ 12 months. Effectiveness of myopia control was defined as any follow-up axial length ≤ baseline axial length, confirming a reduction in axial length. Independent t-test was used to compare the effectiveness of the younger group and the older group with SPSS 22.0. RESULTS: 342 myopic children were included with mean age 8.64 ± 2.20 years and baseline mean axial length of 24.41 ± 1.17 mm. There were 85.40%, 46.30%, 71.20% and 58.30% children with axial length shortening recorded at follow-up for 1 month, 3 months, 6 months and 12 months, respectively. With respect to the axial length shortened eyes, the mean axial length difference (standard deviation) was - 0.039 (0.11) mm, -0.032 (0.11) mm, -0.037 (0.12) mm, -0.028 (0.57) mm at 1, 3, 6, and 12-month follow-up, respectively. Greater AL shortening was observed among the older group who had longer baseline axial lengths than the younger group (P < 0.001). CONCLUSIONS: Overall myopia control effectiveness using photobiomodulation therapy was shown to be age and time related, with the maximum absolute reduction in axial elongation being cumulative.

Fractional picosecond laser treatment of non-acne atrophic scars and scar erythema in Chinese patients.

BACKGROUND: Fractional picosecond lasers (FPL) are reported to be effective and safe for atrophic acne scars and post-acne erythema. However, there is no evidence regarding the effectiveness and safety of FPL treatment for non-acne atrophic scars and scar erythema among Chinese patients. METHODS: In this retrospective study, 12 Chinese patients with non-acne atrophic scars, including nine with scar erythema, were treated with one to three sessions of 1064 nm FPL treatment. Clinical improvement was objectively assessed through blinded evaluations by external physicians. A modified Manchester Scar Scale (mMSS) and the Clinician Erythema Assessment Scale (CEAS) were individually used to evaluate atrophic scars and scar erythema based on photographs. Physician-assessed and subject-assessed Global Aesthetic Improvement Scale (GAIS) were used to assess changes before and after FPL treatment. Patient satisfaction and adverse events were also documented. RESULTS: Total mMSS scores, as well as three parameters (color, distortion, and texture), were significantly decreased after FPL treatment, with a mean reduction of 3.18 ± 1.60 in total scores (p < 0.05). The CEAS scores were significantly reduced from 2.41 ± 0.98 before treatment to 0.41 ± 0.40 at the final visit (p < 0.05). Based on physician-assessed and subject-assessed GAIS scores, 11 (91.7%) patients were improved after FPL treatment. 33.3% of patients were very satisfied, and 41.7% were satisfied. No serious, prolonged (> 3 weeks) adverse events were observed. CONCLUSION: Our study suggests that 1064 nm FPL treatment may be a promising option for non-acne atrophic scars, especially with scar erythema. Further studies are needed to confirm our results.

Low-level laser activates Wnt/ß-catenin signaling pathway-promoting hair follicle stem cell regeneration and wound healing: Upregulate the expression of key downstream gene Lef 1.

BACKGROUND: The objective of this study is to investigate the mechanism by which low-level laser stimulation promotes the proliferation of intraepithelial hair follicle stem cells (HFSCs) in wounds. This research aims to expand the applications of laser treatment, enhance wound repair methods, and establish a theoretical and experimental foundation for achieving accelerated wound healing. METHODS: The experimental approach involved irradiating a cell model with low-level laser to assess the proliferation of HFSCs and examine alterations in the expression of proteins related to the Wnt/ß-catenin signaling pathway. A mouse back wound model was established to investigate the effects of low-level laser irradiation on wound healing rate, wound microenvironment, and the proliferation of HFSCs in relation to the Wnt/ß-catenin signaling pathway. RESULTS: The research findings indicate that low-level laser light effectively activates the Wnt signaling pathway, leading to the increased accumulation of core protein ß-catenin and the upregulation of key downstream gene Lef 1. Consequently, this regulatory mechanism facilitates various downstream biological effects, including the notable promotion of HFSC proliferation and differentiation into skin appendages and epithelial tissues. As a result, the process of wound healing is significantly accelerated. CONCLUSION: Low levels of laser activates the Wnt signalling pathway, promotes the regeneration of hair follicle stem cells and accelerates wound healing.

Selective neural inhibition via photobiomodulation alleviates behavioral hypersensitivity associated with small sensory fiber activation.

OBJECTIVE: Photobiomodulation at higher irradiances has great potential as a pain-alleviating method that selectively inhibits small diameter nerve fibers and corresponding sensory experiences, such as nociception and heat sensation. The longevity and magnitude of these effects as a function of laser irradiation parameters at the nerve was explored. METHODS: In a rodent chronic pain model (spared nerve injury-SNI), light was applied directly at the sural nerve with four delivery schemes: two irradiance levels (7.64 and 2.55 W/cm2 ) for two durations each, corresponding to either 4.8 or 14.4 J total energy, and the effect on sensory hypersensitivities was evaluated. RESULTS: At emitter irradiances of 7.64 W/cm2 (for 240 s), 2.55 W/cm2 (for 720 s), and 7.64 W/cm2 (for 80 s) the heat hypersensitivity was relieved the day following photobiomodulation (PBM) treatment by 37 ± 8.1% (statistically significant, p < 0.001), 26% ± 6% (p = 0.072), and 28 ± 6.1% (statistically significant, p = 0.032), respectively, and all three treatments reduced the hypersensitivity over the course of the experiment (13 days) at a statistically significant level (mixed-design analysis of variance, p < 0.05). The increases in tissue temperature (5.3 ± 1.0 and 1.3 ± 0.4°C from 33.3°C for the higher and lower power densities, respectively) at the neural target were well below those typically associated with permanent action potential disruption. CONCLUSIONS: The data from this study support the use of direct PBM on nerves of interest to reduce sensitivities associated with small-diameter fiber activity.

Efficacy and Safety of 577-nm Yellow Laser in the Treatment of Pigmented Epidermal Lesions.

OBJECTIVES: Freckles and lentigines are common pigmented problems which not only cause substantial cosmetic morbidity but also create psychosocial concern. The available modalities for the treatment of pigmented lesions are often unsatisfactory for patients, require a long treatment period, and often cause skin irritation. With the advent of lasers, safe and effective treatment options for epidermal pigmentation have become more varied for different Fitzpatrick skin types. We aimed to evaluate the efficacy and safety of 577-nm yellow laser in the treatment of pigmented epidermal lesions. METHODS: This study was carried out on 50 patients presented with pigmented epidermal lesions (25 presented with freckles and 25 presented with lentigines). Each patient received four treatment sessions with a 577-nm diode laser at 2-week intervals. RESULTS: There was significant improvement in freckles and lentigines, as 23 out of 50 patients showed marked improvement, 11 patients showed moderate improvement, 10 patients showed mild improvement, and only six patients had no changes. Moreover, 23 patients were very satisfied, 18 patients were satisfied, and nine patients were not satisfied. As regards the safety of the 577-nm yellow laser, there was no significant adverse effect among patients except pain, erythema, and hyperpigmentation, which resolved within one month after treatment. CONCLUSIONS: This study showed that the 577-nm yellow laser is an effective, safe, and well-tolerated device in the treatment of freckles and lentigines.

Exploring Fractional Pigment Toning: A Novel Approach for Treating Benign Pigmented Lesions in Asian Patients With Fitzpatrick Skin Types III-V.

BACKGROUND/OBJECTIVE: Laser therapy has emerged as a widely favored treatment option for solar lentigines (SL). However, a significant challenge associated with this treatment, particularly among individuals with darker skin tones, is the notable risk of postinflammatory hyperpigmentation (PIH) induction. In response to these concerns, the authors conducted a prospective, self-controlled study to comprehensively evaluate the safety and effectiveness of 532-nm picosecond laser, both with and without a microlens array (MLA), for the management of SL in patients with Fitzpatrick skin types (FST) III-V. METHODS: Twenty-seven patients with FST III-V and bilateral SL on the face underwent randomized treatment. One side of the face was treated with a 532-nm picosecond laser coupled with an MLA, utilizing the fractional pigment toning (FPT) technique, while the other side received treatment without the MLA, following the conventional technique (CT). The FPT technique utilized a 9-mm spot size with a fluence of 0.47 J/cm2 for two passes covering 40% of the area. In contrast, the CT used a 4.5-mm handpiece with fluence ranging from 0.3 to 0.7 J/cm2. Patients received a single treatment and were evaluated for pigment clearance, occurrence of PIH, and other adverse effects at 2 weeks, 1, 3, and 6 months posttreatment. RESULTS: Twenty-seven participants completed the study protocol. Analysis of pigment clearance, measured via 3D photography, showed significant improvement from 2 weeks to 6 months posttreatment for both the FPT technique (p < 0.001) and CT (p = 0.004). PIH occurred in 64%, 80%, 96%, and 88% of cases on the CT side, compared to 8%, 32%, 36%, and 16% on the FPT technique side at 2 weeks, 1, 3, and 6 months posttreatment, respectively. The incidence of PIH was significantly lower on the FPT technique side compared to the CT side throughout the follow-up periods. Additionally, transient and mild hypopigmentation occurred in one participant (4%) on the FPT technique side and in five participants (20%) on the CT side. No other adverse effects were observed during the study. CONCLUSIONS: The 532-nm picosecond laser emerges as a safe and efficacious treatment modality for SL in individuals with FST III-V. Particularly noteworthy is the efficacy of the FPT technique, which demonstrates comparable effectiveness while significantly reducing the incidence of PIH compared to the CT.

Picosecond alexandrite laser treatment of nevus of Ota in children.

BACKGROUND: The picosecond alexandrite laser has been safely and effectively used to treat the nevus of Ota in adults. However, limited data are available for children. OBJECTIVE: To investigate the efficacy, safety, and correlative influencing factors of a 755nm picosecond alexandrite laser in the treatment of nevus of Ota in children. METHODS: We retrospectively analyzed Chinese children with nevus of Ota who received a 755nm picosecond alexandrite laser treatment in a tertiary dermatological hospital. RESULT: A total of 305 pediatric patients received an average of two treatments achieving an average of 79% pigment clearance. After the first treatment, 22 patients achieved complete clearance (95%-100%), and 72 patients achieved excellent response (75%-94%), with an average initial efficacy of 63% lesion clearance. Treatment at an early age achieved better initial efficacy (0- to 12-month group >1- to 6-year group, 6- to 12-year group). And 0- to 12-month group achieved better final efficacy. More treatment sessions also increased the final efficacy. Both initial efficacy and final efficacy were better when treating a darker lesion. The incidence of complications was 12.1%, with 10.8% being post-inflammatory hyperpigmentation and 1.3% being hypopigmentation. The rate of recurrence was 6.6%. LIMITATION: Retrospective study. CONCLUSION: A 755nm picosecond alexandrite laser is safe and effective in treating nevus of Ota in children. Younger to initiate treatment, darker lesions, and more treatments are positively associated with better pigmentation clearance.