Does photobiomodulation alter mitochondrial dynamics?

Mitochondrial dysfunction is one of the leading causes of disease development. Dysfunctional mitochondria limit energy production, increase reactive oxygen species generation, and trigger apoptotic signals. Photobiomodulation is a noninvasive, nonthermal technique involving the application of monochromatic light with low energy density, inducing non-thermal photochemical effects at the cellular level, and it has been used due to its therapeutic potential. This review focuses on the mitochondrial dynamic's role in various diseases, evaluating the possible therapeutic role of low-power lasers (LPL) and light-emitting diodes (LED). Studies increasingly support that mitochondrial dysfunction is correlated with severe neurodegenerative diseases such as Parkinson's, Huntington's, Alzheimer's, and Charcot-Marie-Tooth diseases. Furthermore, a disturbance in mitofusin activity is also associated with metabolic disorders, including obesity and type 2 diabetes. The effects of PBM on mitochondrial dynamics have been observed in cells using a human fibroblast cell line and in vivo models of brain injury, diabetes, spinal cord injury, Alzheimer's disease, and skin injury. Thus, new therapies aiming to improve mitochondrial dynamics are clinically relevant. Several studies have demonstrated that LPL and LED can be important therapies to improve health conditions when there is dysfunction in mitochondrial dynamics.

Profiles of Expression of SAV1 in Normoxia or Hypoxia Microenviroment are Associated with Breast Cancer Prognosis.

BACKGROUND: In breast cancer (BC), hypoxia is associated with poor prognosis. Protein Salvador homolog 1 (SAV1) acts as a tumor suppressor and is downregulated in the cancer cells. However, there is limited data on the expression profile of SAV1 and its importance in BC. It has not been studied to evaluate this phenomenon in a hypoxic microenvironment yet. AIM: This study aimed to investigate SAV1 expression profiles under normoxia and hypoxia, and the potential of SAV1 in BC prognosis. METHODS: Gene and protein expression analyses were performed using Real-Time quantitative PCR (RT-qPCR) and immunocytochemistry (ICC), respectively, and in silico analyses were performed using The Cancer Genome Atlas (TCGA). The survival curves were constructed using KMplotter. RESULTS: SAV1 expression was lower in BC samples and tumor cell lines than in normal samples. The SAV1 mRNA levels were reduced in hypoxic estrogen receptor positive (ER+) tumors, which were associated with a lower survival probability as compared to normoxic ER+ tumors. Furthermore, lower levels of SAV1 were found in advanced cancer stage samples, which are associated with worse survival curves and can be a risk factor for BC. CONCLUSIONS: These data suggest a potential prognostic role of SAV1 in BC, with lower expressions associated with worse prognosis.

Photobiomodulation effects in metalloproteinases expression in zymosan-induced arthritis.

Matrix metalloproteinases (MMPs) play a crucial role in the degenerative course of rheumatic disorders. They are responsible for cartilage and other joint-associated tissues breakdown. Amid arthritis treatments, photobiostimulation (PBM), a non-thermal and non-invasive low-power laser application, appears to be an outstanding therapy alternative once it has succeeded in MMPs modulation. Thus, this study aimed to evaluate the PBM effects of low infrared laser (830 nm), testing two different energy densities (3 and 30 Jcm-2) in MMP-2, MMP-9, MMP-13, and MMP-14 as well as the inhibitor TIMP-2 expressions using zymosan-induced arthritis model. C57BL/6 mice were distributed into four groups (n = 8): zymosan-induced arthritis without treatment; zymosan-induced arthritis and dexamethasone-treated; zymosan-induced arthritis and PBM at energy density of 3 Jcm-2 treated; and zymosan-induced arthritis and PBM at energy density of 30 Jcm-2 treated. MMPs and TIMP-2 mRNA relative levels by qRT-PCR and proteins expression by immunohistochemical and Western blotting techniques were performed after PBM treatment in the inflamed joint. Our results demonstrated PBM could modulate both mRNA relative levels and proteins expression of the MMP-2, -9, -13, -14, and TIMP-2 in joint tissues, decreasing MMP-9 protein expression and increasing TIMP-2 protein expression. PBM promotes a better arthritis prognostic, modulating metalloproteinase and its inhibitor, especially MMP-9 and TIMP-2 protein expression that is important inflammatory markers. These findings may also corroborate that PBM may regulate MMPs expression using different pathways.

Low-power infrared laser modulates mRNA levels from genes of base excision repair and genomic stabilization in heart tissue from an experimental model of acute lung injury.

The aim of this study was to evaluate photobiomodulation effects on mRNA relative levels from genes of base excision repair and genomic stabilization in heart tissue from an experimental model of acute lung injury by sepsis. For experimental procedure, animals were randomly assigned to six main groups: (1) control group was animals treated with intraperitoneal saline solution; (2) LASER-10 was animals treated with intraperitoneal saline solution and exposed to an infrared laser at 10 J cm-2; (3) LASER-20 was animals treated with intraperitoneal saline solution and exposed to an infrared laser at 20 J cm-2; (4) acute lung injury (ALI) was animals treated with intraperitoneal LPS (10 mg kg-1); (5) ALI-LASER10 was animals treated with intraperitoneal LPS (10 mg kg-1) and, after 4 h, exposed to an infrared laser at 10 J cm-2 and (6) ALI-LASER20 was animals treated with intraperitoneal LPS (10 mg kg-1) and, after 4 h, exposed to an infrared laser at 20 J cm-2. Irradiation was performed only once and animal euthanasias for analysis of mRNA relative levels by RT-qPCR. Our results showed that there was a reduction of mRNA relative levels from ATM gene and an increase of mRNA relative levels from P53 gene in the heart of animals with ALI when compared to the control group. In addition, there was an increase of mRNA relative levels from OGG1 and APE1 gene in hearts from animals with ALI when compared to the control group. After irradiation, an increase of mRNA relative levels from ATM and OGG1 gene was observed at 20 J cm-2. In conclusion, low-power laser modulates the mRNA relative levels from genes of base excision repair and genomic stabilization in the experimental model of acute lung injury evaluated.

Photodynamic therapy for treatment of bacterial keratitis.

Microbial keratitis is the main cause of corneal opacification and the fourth leading cause of blindness worldwide, with bacteria the major infectious agent. Recently, bacterial keratitis has become a serious threat due to routine use of antibiotics leading to selection of resistant and multidrug-resistant bacteria strains. New approaches for treatment of bacterial keratitis are necessary to outcome the increasing antibiotic resistance. Antimicrobial photodynamic therapy is based on three agents: photosensitizer, oxygen, and light radiation. This therapy has been successful for treatment of infections in different tissues and organs as well as against different type of infectious agents and no resistance development. Also, new photosensitizers are being developed that has increased the spectrum of therapeutic protocols for treatment of a number of infectious diseases. Thus, antimicrobial photodynamic therapy has an extraordinary potential for treatment of those bacterial keratitis cases that actually are not solved by traditional antibiotic therapy.

Antimicrobial photodynamic therapy against Acinetobacter baumannii.

Acinetobacter baumannii (A. baumannii) has emerged as a pathogen of global importance able to cause opportunistic infections on the skin, urinary tract, lungs, and bloodstream, being frequently involved in hospital outbreaks. Such bacterium can resist a variety of environmental conditions and develop resistance to different classes of antibiotics. Antimicrobial photodynamic therapy (aPDT) has been considered a promising approach to overcome bacterial resistance once it does not cause selective environmental pressure on bacteria. In this review, studies on aPDT were accessed on PubMed, and their findings were summarized regarding its efficacy against A. baumannii. The data obtained from the literature show that exogenous photosensitizers belonging to different chemical classes are effective against multidrug-resistant A. baumannii strains. However, most of such data is from in vitro studies, and additional studies are necessary to evaluate if the exogenous photosensitizers may induce selective pressure on A. baumannii and the effectiveness of such photosensitizers in clinical practice.

Nucleotides Cytidine and Uridine Associated with Vitamin B12 vs B-Complex Vitamins in the Treatment of Low Back Pain: The NUBES Study.

PURPOSE: We report the results of low back pain treatment using a combination of nucleotides, uridine (UTP), cytidine (CMP) and vitamin B12, vs a combination of vitamins B1, B6, and B12. PATIENTS AND METHODS: Randomized, double-blind, controlled trial, of a 60-day oral treatment: Group A (n=317) receiving nucleotides+B12 and Group B (n=317) receiving B vitamins. The primary endpoint was the percentage of subjects in each group presenting adverse events (AEs). Secondary endpoints were visual analog scale (VAS) pain scores at Visit 2 (day 30) and Visit 3 (day 60) in relation to pretreatment values, Roland-Morris Questionnaire (RMQ) scores and finger-to-floor distance (FFD) (percentage of subjects per group presenting improvement ≥5 points and ≥3cm, respectively). RESULTS: Seventy-five (24%) and 105 (33%) subjects (P=0.21) presented 133 and 241 AEs, with 3159% of subjects presenting ≥2 AEs (P=0.0019) in Group A and Group B, respectively. Twenty-four subjects in Group B were discontinued due to AEs, while no AE-related discontinuations occurred in Group A (P<0.0001). VAS score reduction after 30 and 60 days of treatment was statistically significant (P<0.0001) in both groups, with Group A showing greater reduction at Visit 2 (P<0.0001). RMQ score improvement ≥5 points occurred in 99% of subjects from each group, and FFD improvement ≥3 cm occurred in all subjects. CONCLUSION: Treatment with nucleotides+B12 was associated with a lower number of total AEs, fewer AEs per subject, and no AE-related treatment discontinuation. Pain intensity (VAS) reduction was superior at 30 days of treatment in the nucleotides+B12 group and equivalent between groups at 60 days of treatment. Improvements in efficacy measures RMQ and FFD were observed in both groups at treatment days 30 and 60.

Effect of low-level laser therapy on the inflammatory response in an experimental model of ventilator-induced lung injury.

The effect of low-level laser therapy (LLLT) on an experimental model of ventilator-induced lung injury (VILI) was evaluated in this study. 24 adult Wistar rats were randomized into four groups: protective mechanical ventilation (PMV), PMV + laser, VILI and VILI + laser. The animals of the PMV and VILI groups were ventilated with tidal volumes of 6 and 35 ml kg-1, respectively, for 90 minutes. After the first 60 minutes of ventilation, the animals in the laser groups were irradiated (808 nm, 100 mW power density, 20 J cm-2 energy density, continuous emission mode, and exposure time of 5 s) and after 30 minutes of irradiation, the animals were euthanized. Lung samples were removed for morphological analysis, bronchoalveolar lavage (BAL) and real time quantitative polynucleotide chain reaction (RT-qPCR). The VILI group showed a greater acute lung injury (ALI) score with an increase in neutrophil infiltration, higher neutrophil count in the BAL fluid and greater cytokine mRNA expression compared to the PMV groups (p < 0.05). The VILI + laser group when compared to the VILI group showed a lower ALI score (0.35 ± 0.08 vs. 0.54 ± 0.13, p < 0.05), alveolar neutrophil infiltration (7.00 ± 5.73 vs. 21.50 ± 9.52, p < 0.05), total cell count (1.90 ± 0.71 vs. 4.09 ± 0.96 × 105, p < 0.05) and neutrophil count in the BAL fluid (0.60 ± 0.37 vs. 2.28 ± 0.48 × 105, p < 0.05). Moreover, LLLT induced a decrease in pro-inflammatory and an increase of anti-inflammatory mRNA levels compared to the VILI group (p < 0.05). In conclusion, LLLT was found to reduce the inflammatory response in an experimental model of VILI.

Low-Power Red and Infrared Laser Effects on Cells Deficient in DNA Repair.

Introduction: Low-level lasers are successfully used to prevent and treat diseases in soft oral and bone tissues, particularly diseases in oral cavity caused by chemotherapy and radiotherapy in oncology. However, controversy exists as to whether these lasers induce molecular side effects, mainly on DNA. The aim of this work was to assess the effects of low-power lasers on mutant Escherichia coli cells in DNA repair. Methods: Escherichia coli wild type cultures as well as those lacking recombination DNA repair (recA -) and la SOS responses (lexA -) irradiated with lasers at different energy densities, powers, and emission modes for cell viability and morphology assessment were used in this study. Results: Laser irradiation: (i) did not affect cell viability of non-mutant and lexA - cells but decreased viability in recA - cultures; (ii) altered morphology of wild type and lexA, depending on the energy density, power, emission mode, and wavelength. Conclusion: Results show that low-level lasers have lethal effects on both recombination DNA repair and SOS response bacterial cells but do not induce morphological modifications in these cells.

Correction to: Photobiomodulation can alter mRNA levels cell death-related.

The authors wish to clarify that Fávia de Paoli refers to "Flávia de Paoli". The authors apologise for this error.

Photobiomodulation can alter mRNA levels cell death-related.

Photobiomodulation (PBM) by low-level laser has demonstrated excellent results for inflammatory treatments, promoting repair of injured tissues. Knowledge regarding the molecular mechanisms involved in this process has been increasing, but its effect on cell death/survival-related gene expression after laser irradiation with different doses is not well understood. So, it is important to know these effects in order to guarantee the safety of therapeutic protocols based on PBM. This study aimed to investigate the mRNA levels of genes related to proteins involved in cell death/survival pathways of healthy tissues from talocrural joint of mice after PBM. Mice were divided into three groups: control, PBM at 3 J cm-2, and PBM at 30 J cm-2. Laser irradiation was performed on talocrural joint during four consecutive days. Morphological analyses, immunocytochemistry, FasL, Fas, Bax, Apaf1, Caspase9, Caspase3, Caspase6, Bcl2 mRNA levels, and DNA fragmentation were performed to verify cell death induction after laser irradiation. PBM can increase mRNA levels of almost genes pro-apoptotic. On the other hand, mRNA level of anti-apoptotic protein Bcl-2 gene was not significantly altered. Bcl-2/Bax ratio (indicator of protective molecular response) was decreased after PBM at 30 J cm-2, trending to DNA fragmentation. Results obtained in this study indicate that PBM by low-level infrared laser alters mRNA relative levels of genes involved in cell death pathways. However, these molecular alterations were not able to cause DNA fragmentation in cells in talocrural joint tissues, indicating that infrared laser was not enough to cause cell death.

Is there a measure for low power laser dose?

Low power lasers have been used successfully for treatment of many diseases in soft and bone tissues. Basic and clinical researches have developed quickly being the scientific basis to therapeutic protocols based on these lasers. However, there are difficulties to compare experimental and clinical results obtained from different researchers because a complicated and intricate list of physical and biological parameters should be checked before the irradiation procedures as well as part of these parameters are omitted or inaccurately reported. This review focuses on the physical and biological parameters proposed to make experimental and clinical protocols accurate and reproducible as well as suggests dose parameters based on biological effects induced by low power lasers. A variety of parameters are reported by different authors and the number of parameter suggested could overcome three dozens. Thus, laser dose and laser dose equivalent are defined based on laser-induced biological effects and suggested as simplified dose parameters for low power lasers. These parameters could simplify and be useful to researchers and clinicians, permitting comparisons and decreasing mistakes and inaccuracies when laser-induced effects are evaluated and compared with those obtained in previous studies. The laser dose and laser dose equivalent could contribute significantly to improve accuracy, effectiveness, and safety of clinical protocols based on low power lasers.

Could adverse effects and complications of selective laser trabeculoplasty be decreased by low-power laser therapy?

Selective laser trabeculoplasty (SLT) has been used for treatment of primary open-angle glaucoma, ocular hypertension, pigmenter and pseudoexfoliative glaucoma being considered a low-risk procedure. Therefore, transitory and permanent adverse effects have been reported, including corneal changes, subclinical edema, and reduction in endothelial cells and in central corneal thickness. Despite rarer, serious corneal complications after SLT can be permanent and lead to visual impairment, central corneal haze, opacity and narrowing. The mechanism involves increase of vasoactive and chemotactic cytokines causing inflammatory infiltrate, destruction of stromal collagen by fibroblasts and increase of matrix metalloproteinases type 2, which impair reepithelization. SLT also increases free radical production and reduces antioxidant enzymes, resulting in endothelium damages. Low-power laser therapy (LPLT) has been used in regenerative medicine based on its biostimulatory and anti-inflammatory effects. Biostimulation occurs through the interaction of laser photons with cytochrome C oxidase enzyme, which activates intracellular biochemical cascades causing synthesis of a number of molecules related to anti-inflammatory, regenerative effects, pain relief and reduction in edema. It has been showed that LPLT reduces gene expression related to pro-inflammatory cytokines and matrix metalloproteinases, and it increases expression of growth factors related to its proliferative and healing actions. Although radiations emitted by low-power lasers are considered safe and able to induce therapeutic effects, researches based on experimental models for glaucoma could bring important data if LPLT could be an alternative approach to improve acceptation for patients undergoing SLT.

Photobiomodulation prevents DNA fragmentation of alveolar epithelial cells and alters the mRNA levels of caspase 3 and Bcl-2 genes in acute lung injury.

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are defined as pulmonary inflammation that could occur from sepsis and lead to pulmonary permeability and alveolar edema making them life-threatening diseases. Photobiomodulation (PBM) properties have been widely described in the literature in several inflammatory diseases; although the mechanisms of action are not always clear, this could be a possible treatment for ARDS/ALI. Thus, the aim of this study was to evaluate the mRNA levels from caspase-3 and BCL-2 genes and DNA fragmentation in lung tissue from Wistar rats affected by ALI and subjected to photobiomodulation by exposure to a low power infrared laser (808 nm; 100 mW; 3.571 W cm-2; four points per lung). Adult male Wistar rats were randomized into 6 groups (n = 5, for each group): control, PBM10 (10 J cm-2, 2 J and 2 seconds), PBM20 (20 J cm-2, 5 J and 5 seconds), ALI, ALI + PBM10 and ALI + PBM20. ALI was induced by intraperitoneal Escherichia coli lipopolysaccharide injection. Lung samples were collected and divided for mRNA expression of caspase-3 and Bcl-2 and DNA fragmentation quantifications. Data show that caspase-3 mRNA levels are reduced and Bcl-2 mRNA levels increased in ALI after low power infrared laser exposure when compared to the non-exposed ALI group. DNA fragmentation increased in inflammatory infiltrate cells and reduced in alveolar cells. Our research shows that photobiomodulation can alter relative mRNA levels in genes involved in the apoptotic process and DNA fragmentation in inflammatory and alveolar cells after lipopolysaccharide-induced acute lung injury. Also, inflammatory cell apoptosis is part of the photobiomodulation effects induced by exposure to a low power infrared laser.

High-Resolution Melting (HRM) of Hypervariable Mitochondrial DNA Regions for Forensic Science.

Forensic strategies commonly are proceeding by analysis of short tandem repeats (STRs); however, new additional strategies have been proposed for forensic science. Thus, this article standardized the high-resolution melting (HRM) of DNA for forensic analyzes. For HRM, mitochondrial DNA (mtDNA) from eight individuals were extracted from mucosa swabs by DNAzol reagent, samples were amplified by PCR and submitted to HRM analysis to identify differences in hypervariable (HV) regions I and II. To confirm HRM, all PCR products were DNA sequencing. The data suggest that is possible discriminate DNA from different samples by HRM curves. Also, uncommon dual-dissociation was identified in a single PCR product, increasing HRM analyzes by evaluation of melting peaks. Thus, HRM is accurate and useful to screening small differences in HVI and HVII regions from mtDNA and increase the efficiency of laboratory routines based on forensic genetics.

Chronic Obstructive Pulmonary Disease: From Injury to Genomic Stability.

Chronic obstructive pulmonary disease (COPD) is the fourth cause of death in the world and it is currently presenting a major global public health challenge, causing premature death from pathophysiological complications and rising economic and social burdens. COPD develops from a combination of factors following exposure to pollutants and cigarette smoke, presenting a combination of both emphysema and chronic obstructive bronchitis, which causes lung airflow limitations that are not fully reversible by bronchodilators. Oxidative stress plays a key role in the maintenance and amplification of inflammation in tissue injury, and also induces DNA damages. Once the DNA molecule is damaged, enzymatic mechanisms act in order to repair the DNA molecule. These mechanisms are specific to repair of oxidative damages, such as nitrogen base modifications, or larger DNA damages, such as double-strand breaks. In addition, there is an enzymatic mechanism for the control of telomere length. All these mechanisms contribute to cell viability and homeostasis. Thus, therapies based on modulation of DNA repair and genomic stability could be effective in improving repair and recovery of lung tissue in patients with COPD.

Apoptosis induced by low-level laser in polymorphonuclear cells of acute joint inflammation: comparative analysis of two energy densities.

Anti-inflammatory property of low-level laser therapy (LLLT) has been widely described in literature, although action mechanisms are not always clarified. Thus, this study aimed to evaluate apoptosis mechanisms in the LLLT anti-inflammatory effects on the arthritis experimental model in vivo at two different energy densities (3 and 30 Jcm-2). Arthritis was induced in mice by zymosan solution, animals were distributed into five groups, and morphological analysis, immunocytochemistry and gene expressions for apoptotic proteins were performed. Data showed an anti-inflammatory effect, DNA fragmentation in polymorphonuclear (PMN) cells and alteration in gene expression of proteins related to apoptosis pathways after LLLT. p53 gene expression increased at both energy densities, Bcl2 gene expression increased at 3 Jcm-2, and Bcl2 tissue expression decreased at 30 Jcm-2. In addition, apoptosis was restricted to PMN cells. Results suggest that apoptosis in PMN cells comprise part of LLLT anti-inflammatory mechanisms by disbalance promotion between expression of pro-apoptotic (Bax and p53) and anti-apoptotic (Bcl-2) proteins, with pro-apoptotic gene expression selectively in PMN cells.

TP53 and ATM mRNA expression in skin and skeletal muscle after low-level laser exposure.

Low-level lasers are widespread in regenerative medicine, but the molecular mechanisms involved in their biological effects are not fully understood, particularly those on DNA stability. Therefore, this study aimed to investigate mRNA expression of genes related to DNA genomic stability in skin and skeletal muscle tissue from Wistar rats exposed to low-level red and infrared lasers. For this, TP53 (Tumor Protein 53) and ATM (Ataxia Telangiectasia Mutated gene) mRNA expressions were evaluated by real-time quantitative PCR (RT-qPCR) technique 24 hours after low-level red and infrared laser exposure. Our data showed that relative TP53 mRNA expression was not significantly altered in both tissues exposed to lasers. For ATM, relative mRNA expression in skin tissue was not significantly altered, but in muscle tissue, laser exposure increased relative ATM mRNA expression. Low-level red and infrared laser radiations alter ATM mRNA expression related to DNA stability in skeletal muscle tissue.

Comparison of the action of diclofenac alone versus diclofenac plus B vitamins on mobility in patients with low back pain.

Objective: To assess results of the finger-to-floor distance (FFD) and the Schober test performed during the DOLOR study, and to verify correlation between Visual Analog Pain Scale scores (VAS) with these measures. Research design and methods: Previously tabulated data from the Clinical Research Forms of the DOLOR study were analyzed (statistical significance defined with a two-tailed p value < 0.05 and confidence interval of 95%). For continuous variables, the Student's T- test or analysis of variance (ANOVA) was used, and differences between pre-treatment and Visits 2, 3, and 4 in the absolute number and percentage of patients with no change, improvement, or worsening of the Schober test and the FFD test scores were calculated, and the results were analyzed with the Chi-squared test. Spearman non-parametric correlation was used for correlating VAS scores with FFD and Schober test scores at each study visit. Main outcome measures: FFD, measured in centimeters; Schober test scores. Results: Throughout the treatment period, there was a statistically significant correlation between the VAS scores and the FFD in the total patient population and within treatment groups. This was not observed for the correlation between the Schober's test scores and the VAS scores. FFD scores within treatment groups improved progressively at each study visit, as did the Schober Test scores. Conclusions: The results of this post-hoc analysis show that combination therapy with diclofenac plus vitamins B1, B6, and B12 had additional positive effects on mobility restoration among the patients of the DOLOR study and serve to highlight the correlation between mobility and pain intensity among patients presenting with low back pain. The two fundamental goals of low back pain therapy are to provide improvements in pain and function. In this sense, the combination of diclofenac with the B vitamins was particularly effective in achieving both of these goals.