Photophysical Mechanisms of Photobiomodulation Therapy as Precision Medicine

Effect of led photobiomodulation on tooth movement, gingival hypertrophy and pain in response to treatment with fixed orthodontic appliance

Photobiomodulation (PBM) is a form of treatment that uses low-power red and near-infrared light to stimulate tissue repair and regeneration at the cellular level. 32 subjects (198 teeth examined), 10 males and 22 females aged 14.6 ± 2.0 years, with mild dental crowding were included in a randomised, controlled clinical trial. The patients were treated with a fixed orthodontic appliance (FOA). Subjects were randomised into an experimental group (a PBM group irradiated with an LED light source with wavelengths of 625 nm, 660 nm and 850 nm simultaneously and an irradiance of 16 mW/cm²) and a placebo control group that received non-therapeutic irradiation with visible light. PBM therapy began within the first 2 days of appliance insertion and was administered twice weekly for 4 weeks. The rate of tooth movement (a change in distance at the same selected point on the occlusal plane of the tooth determined by measurements on 3D models), the presence of gingival hypertrophy (with a free gingival margin of at least 1 mm occlusal to the enamel-cement junction), the plaque index (PI), the sulcus bleeding index (SBI) and the subjective pain sensation using the visual analogue scale (VAS) were monitored. In the experimental PBM group (N = 14), the rate of movement with the FOA was statistically significantly higher at both 1 week of placement (0.5 mm [95%CI: 0.4-0.8]) and 4 weeks (1.1 mm [95%CI: 0.8-1.4]) than in the placebo group (N = 18), where the values were (0.4 mm [95%CI: 0.2-0.5]) at 1 week and (0.6 mm [95%CI: 0.4-0.9]) at 4 weeks. A lower incidence of gingival hypertrophy was observed in the PBM group (21.4%) than in the placebo group (55.6%) after 4 weeks (Mann-Whitney U-test, p < 0.05). PBM with LED accelerated orthodontic tooth movement during the levelling and alignment phase and reduced the incidence of gingival hypertrophy.

The impact of low-level laser therapy (photobiomodulation) on the complications associated with conventional dental treatments and oral disorders: A literature review

Oral health-related quality of life (OHRQoL) refers to how oral conditions impact an individual's social interactions and positive perception of their dental and facial appearance. OHRQoL is a crucial patient-reported outcome in dentistry and typically includes four key dimensions: Oral Function, orofacial pain, orofacial appearance, and Psychosocial impact. The Oral Health Impact Profile (OHIP) is a widely used tool for evaluating OHRQoL due to its strong psychometric properties. It focuses on how individuals perceive the repercussions of oral health issues. Complications arising from oral disorders and dental procedures can significantly disrupt a patient's daily routine, affecting aspects such as diet, sleep, physical activities, and work immediately following the intervention, thereby impacting their overall OHRQoL. Low-level laser therapy (LLLT), also known as "photobiomodulation," has emerged as a promising adjunctive treatment option to reduce inflammation, expedite the healing process, and enhance patients' OHRQoL. LLLT influences various cellular functions, including adenosine triphosphate production, protein and prostaglandin synthesis, neurotransmitter release, cellular growth, differentiation, and phagocytosis. Considering the significance of how oral health issues and associated treatment complications affect patients' OHRQoL, this study aimed to review patient-centered outcome measures in the context of LLLT to evaluate its impact on the complications associated with conventional dental treatments and oral disorders and patients' OHRQoL.

Photobiomodulation in Patients Taking Denosumab: Case Report and Literature Review

Background: Denosumab is a human monoclonal antibody playing a central role in bone resorption. The impaired bone healing observed in patients on denosumab is linked to the drug's inhibition of osteoclast activity. Photobiomodulation (PBM) has garnered attention as a potential adjunctive therapy for managing oral complications in patients on denosumab therapy. The aim of this study is to provide a review of the literature regarding the benefits of photobiomodulation therapy in patients taking denosumab while providing a case report of a patient treated with this therapy. Materials and Methods: Key terms were used to search PubMed (MEDLINE), Scopus, and Web of Science, and at last, 25 articles were compared. Following the proposed review, a case of a patient is illustrated. Results: Based on our literature findings, there are no papers regarding the benefits of photobiomodulation therapy in patients taking denosumab specifically, but there are articles regarding photobiomodulation therapy and MRONJ osteonecrosis patients, which can be caused by denosumab. Discussion: Despite all the limitations of the data in the literature, it can be deduced that there are evident benefits of photobiomodulation therapy in patients taking denosumab. The integration of laser-assisted techniques and photobiomodulation into MRONJ management protocols represents a significant evolution in treatment strategies. Conclusions: Further studies are needed to better understand a potential association between odontoclasts (which can cause external root resorption) and neoplastic disease or medication, as well as to explore the role of photobiomodulation in the therapeutic rehabilitation process.

Electromagnetic radiation and biophoton emission in neuronal communication and neurodegenerative diseases

The intersection of electromagnetic radiation and neuronal communication, focusing on the potential role of biophoton emission in brain function and neurodegenerative diseases is an emerging research area. Traditionally, it is believed that neurons encode and communicate information via electrochemical impulses, generating electromagnetic fields detectable by EEG and MEG. Recent discoveries indicate that neurons may also emit biophotons, suggesting an additional communication channel alongside the regular synaptic interactions. This dual signaling system is analyzed for its potential in synchronizing neuronal activity and improving information transfer, with implications for brain-like computing systems. The clinical relevance is explored through the lens of neurodegenerative diseases and intrinsically disordered proteins, where oxidative stress may alter biophoton emission, offering clues for pathological conditions, such as Alzheimer's and Parkinson's diseases. The potential therapeutic use of Low-Level Laser Therapy (LLLT) is also examined for its ability to modulate biophoton activity and mitigate oxidative stress, presenting new opportunities for treatment. Here, we invite further exploration into the intricate roles the electromagnetic phenomena play in brain function, potentially leading to breakthroughs in computational neuroscience and medical therapies for neurodegenerative diseases.

Photobiomodulation in ocular therapy: current status and future perspectives

Photobiomodulation has been known to have potential medicinal effects for ages. It involves the use of specific wavelengths to target specific regions in the cell. Different health conditions have been reported to be treated with exposure to light such as cardiovascular conditions, inflammatory diseases, infectious diseases, and most importantly ocular diseases. This review specifically targets the treatment of retinal diseases including age-related macular degeneration, diabetic macular edema, myopia and acute retinal light injury with photobiomodulation. Red light is used in this therapy since this wavelength has lower frequency and hence minimal chance of causing any damage. Red light has the potential to penetrate cellular structures such as mitochondria and facilitate cellular processes. For ocular diseases, the target wavelength ranges between 630 to 800 nm. In most of the cases the primary target for red light is the cytochrome C oxidase enzyme in mitochondria, which alters the gene expression and promotes cellular energy production. Clinical evidence shows improvement of visual activity and reduction in thickness of retina post treatment. Future prospects of photobiomodulation involve target-specific treatment, combinational therapy to treat complex retinal diseases including gene therapy, and longitudinal studies to predict long-term efficacy and the chance of any recurrence in the patients. Hence the future of photobiomodulation holds significant potential in medicine especially in ocular diseases characterized by progress in research, technology, and clinical trials.

Photobiomodulation LED Devices for Home Use: Design, Function and Potential: A Pilot Study

Background/Objectives: Many commercial light-emitting diode (LED) devices are available for consumer home usage. The performance characteristics in respect to the dosimetry of many of the devices, currently on direct sale to the public, have not been subject to formal appraisal. In order to 'bridge the gap' between the evidence-based photobiomodulation therapy (PBMT) community and other interested parties, an evaluation is made of a selection of torch type hand-held LED PBMT products currently available for home use. Methods: Five randomly chosen intra-oral and hand-held LED PBMT devices were selected. The optical delivery parameters of the devices were measured, including the beam divergence angle, surface area exposure as well as the output power at the level of the LEDs. The surface and sub-surface temperature changes in porcine tissue samples were assessed under standardised conditions. The manufacturer's patient instructions were correlated to the measured optical parameters. Calculations were made of irradiance and surface radiant exposure. Consumer satisfaction ratings and feedback data were collated, and a relevant statistical analysis conducted. Results: The results were heterogeneous with a wide range of applied wavelengths, output power and irradiance. Power output stability was variable, and, together with a wide beam divergence angle of 74°, the manufacturer's directions for dosimetry were found to be inconsistent with an accurate dose delivery. Conclusions: The manufacturer's proposed dosimetry fails to consider the relevance of the beam divergence angle and optical attenuation in view of the scatter and absorption. Appropriate instructions on how best to gain and optimise an acceptable clinical outcome were inconsistent with an evidence-based approach. Subject to validation by well-planned clinical trials, the concept of home PBMT may open interesting new therapeutic approaches.

Magnetically Stimulated Myogenesis Recruits a CRY2-TRPC1 Photosensitive Signaling Axis

The cryptochromes are flavoproteins that either individually or synergistically respond to light and magnetic field directionality as well as are implicated in circadian rhythm entrainment and development. Single brief exposures (10 min) to low energy (1.5 mT) pulsed electromagnetic fields (PEMFs) were previously shown to enhance myogenesis by stimulating transient receptor potential canonical 1 (TRPC1)-mediated Ca2+ entry, whereby downwardly directed fields produced greater myogenic enhancement than upwardly directed fields. Here, we show that growth in the dark results in myoblasts losing their sensitivity to both magnetic field exposure and directionality. By contrast, overexpressing or silencing cryptochrome circadian regulator 2 (CRY2) in myoblasts enhances or reduces PEMF responses, respectively, under conditions of ambient light. Reducing cellular flavin adenine dinucleotide (FAD) content by silencing riboflavin kinase (RFK) attenuated responsiveness to PEMFs and inhibited selectivity for magnetic field direction. The upregulation of TRPC1 and cell cycle regulatory proteins typically observed in response to PEMF exposure was instead attenuated by upwardly directed magnetic fields, growth in the darkness, magnetic shielding, or the silencing of CRY2 or RFK. A physical interaction between CRY2 and TRPC1 was detected using coimmunoprecipitation and immunofluorescence, revealing their co-translocation into the nucleus after PEMF exposure. These results implicate CRY2 in an identified TRPC1-dependent magnetotransduction myogenic cascade.

Reprogramming Macrophage Phenotypes With Photobiomodulation for Improved Inflammation Control in ENT Organ Tissues

Photobiomodulation (PBM), a noninvasive phototherapy that utilizes wavelengths between red and near-infrared light, has emerged as a promising approach for controlling inflammation by modulating macrophage polarization. This review investigates the therapeutic potential of PBM in treating ENT-specific inflammatory conditions, such as chronic rhinosinusitis and otitis media, focusing on its effects on macrophage phenotypes and evidence from preclinical studies. By promoting mitochondrial activity, increasing adenosine triphosphate production, and modulating reactive oxygen species, PBM has been shown to shift macrophages from a pro-inflammatory to an anti-inflammatory phenotype. Studies have demonstrated that PBM enhances tissue repair, reduces inflammatory markers, and promotes wound healing. Moreover, PBM facilitates the polarization of M2 macrophages, a crucial factor in resolving mucosal inflammation in the nasal, pharyngeal, and middle ear cavities, as well as restoring tissue homeostasis. The anti-inflammatory effects of PBM are attributed to its ability to influence several molecular mechanisms involved in inflammation regulation, particularly in ENT organ tissues, where recurrent inflammation can lead to chronic conditions such as otitis media or sinusitis. Furthermore, this review compares PBM to competing methods for reprogramming macrophages and treating inflammation, highlighting its advantages of minimal toxicity, simplicity, and precision in controlling ENT immune responses.

A combination of gold nanoparticles and laser photobiomodulation to boost antioxidant defenses in the recovery of muscle injuries caused by Bothrops jararaca venom

This study aimed to evaluate gold nanoparticles (GNPs) and photobiomodulation (PBM), associated with antibothropic serum (AS), to treat a muscle lesion induced by Bothrops jararaca venom.

METHODS

108 Swiss male mice were used, divided into nine groups (n = 12) with different combinations of treatments. Animals were inoculated with 250 µg of B. jararaca venom at the right gastrocnemius muscle. The treatment started 12 h after the venom injection and occurred daily for 7 days. AS was administered as recommended by the Ministry of Health. Low-power aluminum gallium indium phosphide (AlGaInP) with continuous emission (wavelength 660 nm; average power 30 mW ± 20%; beam size of 0.06310 cm2; and dose of 2 J for ± 1 min per point). Irradiation was applied to five distinct areas surrounding the wound, at a perpendicular angle to the skin. The groups treated with GNPs received treatment through the application of 1 mL of 20 nm GNPs (30 mg/L). Muscle, heart, and kidneys were removed for histological and biochemical analysis.

RESULTS

GNPs can improve the results achieved by PBM and the standard treatment, presenting significant benefits in histological parameters, such as the increase of new blood vessels, fibroblasts, collagen, and a reduction of inflammatory infiltrate.

CONCLUSION

GNPs can be considered an option to accelerate the recovery of Bothrops lesions.

The Effects of High-Intensity Laser Therapy vs. Low-Level Laser Therapy on Functional Ability and Quadriceps Architecture in Patients with Knee Osteoarthritis: A Single-Blinded Randomized Clinical Trial

Introduction: This study aimed to compare the effects of high-intensity laser therapy (HILT) and low-level laser therapy (LLLT) on the disability and architecture of the quadriceps in patients with knee osteoarthritis (OA). Methods: Ninety-eight patients with knee OA (KOA) were selected by convenience sampling and then divided into three groups: control, LLLT and HILT. Disability was determined using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Quadriceps structures including thickness, fascicle length and pennate angle of the vastus lateralis (VL) and thickness, volume and fiber angle of vastus medialis obliquus (VMO) muscles were assessed using ultrasonography. All evaluations were performed before interventions, immediately after interventions, and one month later. Between-group data were analyzed with two-way ANOVA and paired-samples t-test. Results: The within-group comparisons of WOMAC scores before, after and at a one-month follow-up showed significant differences between the groups (P<0.001). The VMO thickness revealed significant increases after the treatment in both HILT (P<0.001) and LLLT (P=00.03) groups. The between-group comparison revealed a significantly lower score of WOMAC in the HILT group compared to the other groups after a one-month follow-up (P=00.03). VMO thickness showed a significant increase in the HILT group after the treatment (P=0.002). The VL structures and VMO fiber angle and volume did not exhibit significant changes in within-group and between-group comparisons (P>00.05). Conclusion: Both HILT and LLLT may improve functional ability and VMO thickness in patients with knee osteoarthritis. After a one-month follow-up, functional ability was greater in the HILT group.

The Role of Photobiomodulation to Modulate Ion Channels in the Nervous System: A Systematic Review

Photobiomodulation (PBM) is a safe and effective neurotherapy that modulates cellular pathways by altering cell membrane potentials, leading to beneficial biological effects such as anti-inflammatory and neuroregenerative responses. This review compiles studies from PubMed up to March 2024, investigating the impact of light at wavelengths ranging from 620 to 1270 nm on ion channels. Out of 330 articles screened, 19 met the inclusion criteria. Research indicates that PBM can directly affect various ion channels by influencing neurotransmitter synthesis in neighboring cells, impacting receptors like glutamate and acetylcholine, as well as potassium, sodium channels, and transient receptor potential channels. The diversity of studies hampers a comprehensive meta-analysis for evaluating treatment strategies effectively. This systematic review aims to explore the potential role of optoelectronic signal transduction in PBM, studying the neurobiological mechanisms and therapeutic significance of PBM on ion channels. However, the lack of uniformity in current treatment methods underscores the necessity of establishing standardized and reliable therapeutic approaches.

Investigating the Effect of Photobiomodulation Therapy With Different Wavelengths of Diode Lasers on the Proliferation and Adhesion of Human Gingival Fibroblast Cells to a Collagen Membrane: An In Vitro Study

Introduction: Photobiomodulation (PBM) is considered a promising adjunctive approach in regenerative medicine. This study aimed to investigate the proliferation and adhesion of human gingival fibroblast (HGF) cells to a collagen membrane following PBM. Methods: Cultured HGF cells on a collagen membrane received PBM at wavelengths of 808 nm, 915 nm (2 and 4 J/cm2), and 660 nm (2.1 and 4.2 J/cm2) in interventional groups, while non-irradiated cells served as the control. On days 1 and 3 post-irradiation, cell proliferation was measured by MTT assay, and adhesion to the membrane was assessed under the scanning electron microscope (SEM). Results: Cell proliferation significantly increased in interventional groups compared to the control, with the most significant increase at 915 nm (4 J/cm2) in both time points. On the first day, the 808 nm and 660 nm lasers demonstrated similar results, significantly lower than the 915 nm laser (2 J/cm2). On day 3, the 660 nm, 808 nm, and 915 nm (2 J/cm2) groups showed comparable results. Qualitative analysis by the SEM identified spindle-shaped cells with multiple extended projections in 915 nm groups, especially at an energy density of 4 J/cm2. Groups of 660 nm and 808 nm (4 J/cm2) showed spindle-shaped cell morphology. No distinct cellular morphology indicative of enhanced adhesion was observed at 808 nm (2 J/cm2). Conclusion: The most effective PBM setup for promoting HGF proliferation and adhesion to a collagen membrane was identified at 915 nm (4 J/cm2).

Modifying Alzheimer's disease pathophysiology with photobiomodulation: model, evidence, and future with EEG-guided intervention

This manuscript outlines a model of Alzheimer's Disease (AD) pathophysiology in progressive layers, from its genesis to the development of biomarkers and then to symptom expression. Genetic predispositions are the major factor that leads to mitochondrial dysfunction and subsequent amyloid and tau protein accumulation, which have been identified as hallmarks of AD. Extending beyond these accumulations, we explore a broader spectrum of pathophysiological aspects, including the blood-brain barrier, blood flow, vascular health, gut-brain microbiodata, glymphatic flow, metabolic syndrome, energy deficit, oxidative stress, calcium overload, inflammation, neuronal and synaptic loss, brain matter atrophy, and reduced growth factors. Photobiomodulation (PBM), which delivers near-infrared light to selected brain regions using portable devices, is introduced as a therapeutic approach. PBM has the potential to address each of these pathophysiological aspects, with data provided by various studies. They provide mechanistic support for largely small published clinical studies that demonstrate improvements in memory and cognition. They inform of PBM's potential to treat AD pending validation by large randomized controlled studies. The presentation of brain network and waveform changes on electroencephalography (EEG) provide the opportunity to use these data as a guide for the application of various PBM parameters to improve outcomes. These parameters include wavelength, power density, treatment duration, LED positioning, and pulse frequency. Pulsing at specific frequencies has been found to influence the expression of waveforms and modifications of brain networks. The expression stems from the modulation of cellular and protein structures as revealed in recent studies. These findings provide an EEG-based guide for the use of artificial intelligence to personalize AD treatment through EEG data feedback.

Transcranial Photobiomodulation Therapy as an Intervention for Opioid Cravings and Depression: A Pilot Cohort Study

Introduction: The opioid crisis, a declared national health emergency, has prompted the exploration of innovative treatments to address the pervasive issues of opioid cravings and associated depression. Aims: This pilot cohort study investigated the efficacy of transcranial Photobiomodulation (tPBM) therapy using the SunPowerLED helmet to alleviate these symptoms in individuals undergoing treatment for opioid addiction at a rehabilitation center in West Virginia. Methods: Employing a quasi-experimental design, this study enrolled participants into two groups: one receiving tPBM therapy alongside standard care and a control group receiving standard care alone. The helmet features include the following: total wavelength = 810 nm, total irradiance = 0.06 W/cm2 (60 m W/cm2), and total fluence = 172.8J/cm2. Results: The results of the Wilcoxon signed-rank tests for within-group analysis and Mann-Whitney U tests for between-group comparisons revealed statistically significant reductions in the intensity (W = 7.36, p = 0.012), time (W = 6.50, p = 0.015), frequency (W = 6.50, p = 0.010), and total scores of opioid cravings (W = 7.50, p = 0.009), as well as improvements in depression symptoms (W= 8.00, p = 0.005) within the PBM group compared to the non-PBM group. Discussion: These findings suggest that transcranial PBM therapy could be a promising noninvasive intervention for reducing opioid cravings and depressive symptoms in individuals with opioid use disorder, warranting further investigation through larger randomized controlled trials.

Cross-Over Study Evaluating Photobiomodulation in Pain Control in the Lower Limb

Introduction Photobiomodulation is an emerging treatment modality in dermatology, with increasing use in doctors' offices. Photobiomodulation is the use of various light sources in the red light (620-700 nm) and near-infrared (700-1440 nm) spectrums as a form of light therapy. Objective The objective of the present study was to evaluate the use of photobiomodulation to improve pain in patients who take analgesics daily for chronic non-arterial leg ulcers. Method A cohort trial was performed with 20 patients to evaluate the improvement in pain, patient tolerance to treatment, and evolution of chronic, difficult-to-heal leg ulcers treated with low-frequency laser. Data were entered into a Microsoft Excel spreadsheet (Microsoft Corporation, Redmond, WA, US). Statistical analysis used the Stats Direct 3 program with significance being set at an alpha error of 5% (p-value <0.05). Results An improvement in pain immediately after the first session was experienced by 18/20 patients; these patients remained pain-free for at least four days. One patient had suffered much pain during the entire day; a biopsy with culture and antibiogram was performed with the pain improving after treating an infection with appropriate antibiotics. However, one other case reported no improvement in the pain. Conclusion Photobiomodulation is an optional adjuvant therapy to improve pain in the treatment of chronic, difficult-to-heal leg ulcers.

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.

The impact of formaldehyde exposure on lung inflammatory disorders: Insights into asthma, bronchitis, and pulmonary fibrosis

Lung inflammatory disorders are a major global health burden, impacting millions of people and raising rates of morbidity and death across many demographic groups. An industrial chemical and common environmental contaminant, formaldehyde (FA) presents serious health concerns to the respiratory system, including the onset and aggravation of lung inflammatory disorders. Epidemiological studies have shown significant associations between FA exposure levels and the incidence and severity of several respiratory diseases. FA causes inflammation in the respiratory tract via immunological activation, oxidative stress, and airway remodelling, aggravating pre-existing pulmonary inflammation and compromising lung function. Additionally, FA functions as a respiratory sensitizer, causing allergic responses and hypersensitivity pneumonitis in sensitive people. Understanding the complicated processes behind formaldehyde-induced lung inflammation is critical for directing targeted strategies aimed at minimizing environmental exposures and alleviating the burden of formaldehyde-related lung illnesses on global respiratory health. This abstract explores the intricate relationship between FA exposure and lung inflammatory diseases, including asthma, bronchitis, allergic inflammation, lung injury and pulmonary fibrosis.

Photobiomodulation effects on synovial morphology, iNOS gene, and protein expression in a model of acute inflammation

PURPOSE

To evaluate morphological aspects and inducible nitric oxide synthase (iNOS) gene and protein expression in a model of acute inflammation.

METHODS

Thirty-six female Wistar rats were assigned into three groups: control (saline, n = 12), sham (arthritis, n = 12), and PBM (arthritis and photobiomodulation, n = 12). Arthritis induction was performed with 200 μg of intra-articular Zymosan in sham and PBM animals. PBM was performed 24 h after induction with a laser device (λ = 808 nm, 25 mW of nominal power, fluence of 20 J/cm2, beam area of 0.02 mm2, time of 33 s, total energy of 0.825 J) with punctual and single dose application. Morphological analysis of joint structure (HE) and immunohistochemistry (anti-iNOS antibody) were performed on knee samples, and synovial tissue was submitted to RNA extraction, cDNA synthesis and gene expression analysis by quantitative polymerase chain reaction. Statistical analyses were performed with p < 0.05.

RESULTS

It was observed an increase in the thickness of the synovial lining epithelium and inflammatory infiltrate in sham compared to PBM. Gene expression analysis showed higher iNOS expression in PBM, and iNOS protein expression decreased in PBM compared to sham.

CONCLUSIONS

Photobiomodulation decreased inflammation in PBM animals, upregulated iNOS gene expression, however down egulated protein expression compared to sham.

The Effects In Vitro of Photobiomodulation Over Fibroblasts and Extracellular Matrix

Objective: The objective of this study is to evaluate the potential effects of photobiomodulation (PBM) on cell proliferation and extracellular matrix production of human fibroblasts (FN1) cultured in 2D. Background: Patients with healing difficulties suffer injuries that take time to recover. In addition, aging can be seen in our faces daily when we look in the mirror; in both situations, collagen production is reduced. Fibroblasts act in the beginning and at the end of the inflammation phase, signaling to immune agents, and platelets, and producing collagen, coordinating repair. PBM increases cell viability, proliferation, and mRNA production. Methods: Human fibroblasts were irradiated three times after cell seed (after 24, 48, and 72 h) using a gallium-aluminum arsenideGaAlAs low-level laser (LLL). Cell viability, proliferative response, synthesis of collagen types I and III, and soluble collagen production were analyzed. The statistical significance of differences between groups was determined using unpaired one-way analysis of variance (ANOVA) p < 0.05. Results: PBM increased significantly the number of fibroblasts, and the production of collagen types I (Col I) and III (Col III), after three sessions of LLL with 2.5 J per session, every 24 h, for 3 consecutive days; total energy delivered after 72 h is 7.5 J. Conclusions: This energy density of LLL increases fibroblast proliferation and collagen production in vitro without side effects.

A comprehensive review on therapeutic potentials of photobiomodulation for neurodegenerative disorders

A series of experimental trials over the past two centuries has put forth Photobiomodulation (PBM) as a treatment modality that utilizes colored lights for various conditions. While in its cradle, PBM was used for treating simple conditions such as burns and wounds, advancements in recent years have extended the use of PBM for treating complex neurodegenerative diseases (NDDs). PBM has exhibited the potential to curb several symptoms and signs associated with NDDs. While several of the currently used therapeutics cause adverse side effects alongside being highly invasive, PBM on the contrary, seems to be broad-acting, less toxic, and non-invasive. Despite being projected as an ideal therapeutic for NDDs, PBM still isn't considered a mainstream treatment modality due to some of the challenges and knowledge gaps associated with it. Here, we review the advantages of PBM summarized above with an emphasis on the common mechanisms that underlie major NDDs and how PBM helps tackle them. We also discuss important questions such as whether PBM should be considered a mainstay treatment modality for these conditions and if PBM's properties can be harnessed to develop prophylactic therapies for high-risk individuals and also highlight important animal studies that underscore the importance of PBM and the challenges associated with it. Overall, this review is intended to bring the major advances made in the field to the spotlight alongside addressing the practicalities and caveats to develop PBM as a major therapeutic for NDDs.

Harmonizing Magnetic Mitohormetic Regenerative Strategies: Developmental Implications of a Calcium-Mitochondrial Axis Invoked by Magnetic Field Exposure

Mitohormesis is a process whereby mitochondrial stress responses, mediated by reactive oxygen species (ROS), act cumulatively to either instill survival adaptations (low ROS levels) or to produce cell damage (high ROS levels). The mitohormetic nature of extremely low-frequency electromagnetic field (ELF-EMF) exposure thus makes it susceptible to extraneous influences that also impinge on mitochondrial ROS production and contribute to the collective response. Consequently, magnetic stimulation paradigms are prone to experimental variability depending on diverse circumstances. The failure, or inability, to control for these factors has contributed to the existing discrepancies between published reports and in the interpretations made from the results generated therein. Confounding environmental factors include ambient magnetic fields, temperature, the mechanical environment, and the conventional use of aminoglycoside antibiotics. Biological factors include cell type and seeding density as well as the developmental, inflammatory, or senescence statuses of cells that depend on the prior handling of the experimental sample. Technological aspects include magnetic field directionality, uniformity, amplitude, and duration of exposure. All these factors will exhibit manifestations at the level of ROS production that will culminate as a unified cellular response in conjunction with magnetic exposure. Fortunately, many of these factors are under the control of the experimenter. This review will focus on delineating areas requiring technical and biological harmonization to assist in the designing of therapeutic strategies with more clearly defined and better predicted outcomes and to improve the mechanistic interpretation of the generated data, rather than on precise applications. This review will also explore the underlying mechanistic similarities between magnetic field exposure and other forms of biophysical stimuli, such as mechanical stimuli, that mutually induce elevations in intracellular calcium and ROS as a prerequisite for biological outcome. These forms of biophysical stimuli commonly invoke the activity of transient receptor potential cation channel classes, such as TRPC1.

Epilepsy: Mitochondrial connections to the 'Sacred' disease

Over 65 million people suffer from recurrent, unprovoked seizures. The lack of validated biomarkers specific for myriad forms of epilepsy makes diagnosis challenging. Diagnosis and monitoring of childhood epilepsy add to the need for non-invasive biomarkers, especially when evaluating antiseizure medications. Although underlying mechanisms of epileptogenesis are not fully understood, evidence for mitochondrial involvement is substantial. Seizures affect 35%-60% of patients diagnosed with mitochondrial diseases. Mitochondrial dysfunction is pathophysiological in various epilepsies, including those of non-mitochondrial origin. Decreased ATP production caused by malfunctioning brain cell mitochondria leads to altered neuronal bioenergetics, metabolism and neurological complications, including seizures. Iron-dependent lipid peroxidation initiates ferroptosis, a cell death pathway that aligns with altered mitochondrial bioenergetics, metabolism and morphology found in neurodegenerative diseases (NDDs). Studies in mouse genetic models with seizure phenotypes where the function of an essential selenoprotein (GPX4) is targeted suggest roles for ferroptosis in epilepsy. GPX4 is pivotal in NDDs, where selenium protects interneurons from ferroptosis. Selenium is an essential central nervous system micronutrient and trace element. Low serum concentrations of selenium and other trace elements and minerals, including iron, are noted in diagnosing childhood epilepsy. Selenium supplements alleviate intractable seizures in children with reduced GPX activity. Copper and cuproptosis, like iron and ferroptosis, link to mitochondria and NDDs. Connecting these mechanistic pathways to selenoproteins provides new insights into treating seizures, pointing to using medicines including prodrugs of lipoic acid to treat epilepsy and to potential alternative therapeutic approaches including transcranial magnetic stimulation (transcranial), photobiomodulation and vagus nerve stimulation.

New Insights into Photobiomodulation of the Vaginal Microbiome-A Critical Review

The development of new technologies such as sequencing has greatly enhanced our understanding of the human microbiome. The interactions between the human microbiome and the development of several diseases have been the subject of recent research. In-depth knowledge about the vaginal microbiome (VMB) has shown that dysbiosis is closely related to the development of gynecologic and obstetric disorders. To date, the progress in treating or modulating the VMB has lagged far behind research efforts. Photobiomodulation (PBM) uses low levels of light, usually red or near-infrared, to treat a diversity of conditions. Several studies have demonstrated that PBM can control the microbiome and improve the activity of the immune system. In recent years, increasing attention has been paid to the microbiome, mostly to the gut microbiome and its connections with many diseases, such as metabolic disorders, obesity, cardiovascular disorders, autoimmunity, and neurological disorders. The applicability of PBM therapeutics to treat gut dysbiosis has been studied, with promising results. The possible cellular and molecular effects of PBM on the vaginal microbiome constitute a theoretical and promising field that is starting to take its first steps. In this review, we will discuss the potential mechanisms and effects of photobiomodulation in the VMB.

Relationship between Laser Intensity at the Peripheral Nerve and Inhibitory Effect of Percutaneous Photobiomodulation on Neuronal Firing in a Rat Spinal Dorsal Horn

Photobiomodulation is an effective treatment for pain. We previously reported that the direct laser irradiation of the exposed sciatic nerve inhibited firing in the rat spinal dorsal horn evoked by mechanical stimulation, corresponding to the noxious stimulus. However, percutaneous laser irradiation is used in clinical practice, and it is unclear whether it can inhibit the firing of the dorsal horn. In this study, we investigated whether the percutaneous laser irradiation of the sciatic nerve inhibits firing. Electrodes were inserted into the lamina II of the dorsal horn, and mechanical stimulation was applied using von Frey filaments (vFFs) with both pre and post laser irradiation. Our findings show that percutaneous laser irradiation inhibited 26.0 g vFF-evoked firing, which corresponded to the noxious stimulus, but did not inhibit 0.6 g and 8.0 g vFF-evoked firing. The post- (15 min after) and pre-irradiation firing ratios were almost the same as those for direct and percutaneous irradiation. A photodiode sensor implanted in the sciatic nerve showed that the power density reaching the sciatic nerve percutaneously was attenuated to approximately 10% of that on the skin. The relationship between the laser intensity reaching the nerve and its effect could be potentially useful for a more appropriate setting of laser conditions in clinical practice.

Photobiomodulation in Alzheimer's Disease-A Complementary Method to State-of-the-Art Pharmaceutical Formulations and Nanomedicine?

Alzheimer's disease (AD), as a neurodegenerative disorder, usually develops slowly but gradually worsens. It accounts for approximately 70% of dementia cases worldwide, and is recognized by WHO as a public health priority. Being a multifactorial disease, the origins of AD are not satisfactorily understood. Despite huge medical expenditures and attempts to discover new pharmaceuticals or nanomedicines in recent years, there is no cure for AD and not many successful treatments are available. The current review supports introspection on the latest scientific results from the specialized literature regarding the molecular and cellular mechanisms of brain photobiomodulation, as a complementary method with implications in AD. State-of-the-art pharmaceutical formulations, development of new nanoscale materials, bionanoformulations in current applications and perspectives in AD are highlighted. Another goal of this review was to discover and to speed transition to completely new paradigms for the multi-target management of AD, to facilitate brain remodeling through new therapeutic models and high-tech medical applications with light or lasers in the integrative nanomedicine of the future. In conclusion, new insights from this interdisciplinary approach, including the latest results from photobiomodulation (PBM) applied in human clinical trials, combined with the latest nanoscale drug delivery systems to easily overcome protective brain barriers, could open new avenues to rejuvenate our central nervous system, the most fascinating and complex organ. Picosecond transcranial laser stimulation could be successfully used to cross the blood-brain barrier together with the latest nanotechnologies, nanomedicines and drug delivery systems in AD therapy. Original, smart and targeted multifunctional solutions and new nanodrugs may soon be developed to treat AD.