Low-level laser irradiation effect on endothelial cells under conditions of hyperglycemia

Effects and parameterization of low-level laser therapy in diabetic ulcers: an umbrella review of systematic reviews and meta-umbrella

This study aimed to systematically verify the available systematic reviews and meta-analyses of Low-level laser therapy (LLLT) in diabetic foot ulcer (DFUs) to identify the effects and optimal parameters of LLLT in the management of DFUs. This umbrella review was written according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) report items and registered in the International Prospective Register of Systematic Review (PROSPERO). The search for articles was performed in the Pubmed, Scopus, Web of Science and Embase databases. The following terms were used: Diabetic Foot, Diabetic Neuropathies, Peripheral Vascular Diseases, Peripheral Neuropathy, Diabetic Foot Ulcer, LASER Therapy, Low-Level Light Therapy, LLLT, LASER Biostimulation, Low Intensity LASER Irradiation, Low Power LASER Irradiation, Low Intensity LASER Therapy, Low Power LASER Therapy. A search was performed in the references section of the included studies. The systematic review (SR) included studies that compared LLLT with non-therapeutic doses (parameters considered low to modify healing), sham irradiation, and conventional DFU treatment. The interventions were performed using red and infrared wavelengths. Although two studies included in the SR used wavelengths below 600 nm, these were combined with diodes with infrared wavelengths within the same device. Another study performed a comparative analysis of LLLT at different wavelengths (632 nm and 904 nm), with area reduction rates of 63.7% and 56.8%, respectively, with no statistically significant difference. This is study indicated that, compared with standard treatment and non-irradiation treatments, the use of photobiomodulation (PBM) with different parameters was effective in promoting UPD healing. Further studies are warranted to determine the ideal parameters for improving patient outcomes. (International Prospective Register of Systematic Review Registration number: CRD42022362447).

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL TRIAL REGISTRATION NUMBER

NCT04246814.

An evaluation of photobiomodulation effects on human gingival fibroblast cells under hyperglycemic condition: an in vitro study

An in vitro study was designed to evaluate the effects of photobiomodulation (PBM) with 915-nm diode laser on human gingival fibroblast (HGF) cells under hyperglycemic condition. The HGF cells were cultured in Dulbecco's modified eagle medium (DMEM) medium containing 30 mM glucose concentration for 48 h to mimic the hyperglycemic condition. Subsequently, the cells received three sessions of PBM (915 nm, continuous emission mode, 200 mW, energy density values of 3.2, 6, and 9.2 J/cm2). Twenty-four hours post-irradiation, cell proliferation, expression of interleukin 6 (IL-6), and vascular endothelial growth factor (VEGF) were assessed with MTT and real-time polymerase chain reaction (PCR) tests, respectively. Also, reactive oxygen species (ROS) production was measured using CM-H2DCFDA fluorimetry. No changes were detected in the cell proliferation rate between the high glucose control group and laser-treated cells, while VEGF and IL-6 gene expression levels increased significantly after PBM in the high glucose-treated cells group. ROS level was significantly decreased in the irradiated cells in high-glucose medium compared with the high glucose control group. Our study revealed the inductive role of 915-nm-mediated PBM on VEGF and the inflammatory response while concurrently reducing reactive oxygen species production in HGF cells in hyperglycemic conditions.

Physical therapy in diabetic foot ulcer: Research progress and clinical application

Diabetes foot ulcer (DFU) is one of the most intractable complications of diabetes and is related to a number of risk factors. DFU therapy is difficult and involves long-term interdisciplinary collaboration, causing patients physical and emotional pain and increasing medical costs. With a rising number of diabetes patients, it is vital to figure out the causes and treatment techniques of DFU in a precise and complete manner, which will assist alleviate patients' suffering and decrease excessive medical expenditure. Here, we summarised the characteristics and progress of the physical therapy methods for the DFU, emphasised the important role of appropriate exercise and nutritional supplementation in the treatment of DFU, and discussed the application prospects of non-traditional physical therapy such as electrical stimulation (ES), and photobiomodulation therapy (PBMT) in the treatment of DFU based on clinical experimental records in ClinicalTrials.gov.

Effects of photobiomodulation therapy (PBMT) over endothelial function in healthy individuals: a preliminary crossover clinical trial

Photobiomodulation therapy (PBMT) causes stimulatory effects that raise cell metabolism. The study aimed to evaluate the effects of PBMT on the endothelial function of healthy individuals. It was a controlled, randomized, crossover, triple-blind trial with 22 healthy volunteers (female: 77.3%), aged 25.45 years which were randomly divided into three groups. PBMT with gallium-aluminum-arsenide (GaAlAs) diode laser (810 nm, continuous-wave mode, 1000 mW, 0.28 cm²) was applied over the radial and ulnar artery regions in two parallel spots: group 1-30 J (n = 22, 107 J/cm²) per spot; group 2-60 J (n = 22, 214 J/cm²) per spot; and group 3-placebo (n = 22, sham). The endothelial function was measured before and immediately after PBMT by the flow-mediated dilation technique (%FMD) with high-resolution ultrasound. Statistical analysis was made with ANOVA for repeated measures, the effect size was measured by Cohen's d, and results are presented as mean and standard error (or 95% confidence intervals). A p-value < 0.05 was considered statistically significant. The %FMD increases 10.4% with 60 J (mean difference = 0.496 mm, 95% CI = 0.42 to 0.57, p < 0.001), 7.3% with 30 J (mean difference = 0.518 mm, 95% CI = 0.44 to 0.59, p < 0.001), and 4.7% with placebo (mean difference = 0.560 mm, 95% CI = 0.48 to 0.63, p < 0.001). We found a small effect size (p = 0.702; d de Cohen = 0.24) without statistical difference between interventions. PBMT with the energy density of 60 J and 30 J did not improve endothelial function.Trial registration number: NCT03252184 (01/09/2017).

Serum and salivary cytokines in patients with oral lichen planus treated with Photobiomodulation

OBJECTIVES

To evaluate the serum and salivary levels of IL-1β, IL-6, IL-17A, TNF-α, IL-4, and IL-10 in patients with oral lichen planus (OLP) treated with Photobiomodulation (PBM) and clobetasol propionate 0.05%.

MATERIAL AND METHODS

Thirty-four OLP patients were randomized into two groups: Control (clobetasol propionate 0.05%) and PBM (660 nm, 100 mW, 177 J/cm2 , 5 s, 0.5 J per point). Serum and saliva were collected at baseline and at the end of treatment (after 30 days) and evaluated using ELISA. The cytokine results were correlated with pain, clinical subtypes, and clinical scores of OLP.

RESULTS

IL-1β, IL-6, IL-17A, TNF-α, and IL-4 levels were higher in saliva in relation to serum. IL-1β was the most concentrated cytokine in saliva, and a positive correlation with the severity of OLP was noticed. After treatment with corticosteroid, IL-1β in saliva decreased significantly. No modulation of all cytokines was observed after PBM.

CONCLUSION

IL-1β appears to be an important cytokine involved in OLP pathogenesis. In addition, the mechanisms of action of PBM do not seem to be linked to the modulation of pro or anti-inflammatory cytokines at the end of treatment. It is possible that this events occurred early during treatment.

Photobiomodulation promotes angiogenesis in wound healing through stimulating the nuclear translocation of VEGFR2 and STAT3

In recent years, Photobiomodulation (PBM) has gained prevalence as a kind of physical therapy for wound healing, however, concerning specific cellular mechanisms induced by PBM remains uncertain. The objective of this study is to evaluate the mechanisms of action of PBM (632.8 nm) on angiogenesis in wound healing in vitro and vivo. In the present work, we indicated that PBM with 1.0 J/cm2 irradiation dose exerts positive effects on cell viability, migration, proliferation and tube formation in human umbilical vein endothelial cells (HUVECs). Furthermore, we demonstrate that the VEGFA/VEGFR2/STAT3 pathway plays an important role in PBM effecting cellular function and promoting angiogenesis in wound healing. In addition, we also found that PBM activated the VEGFA/VEGFR2/STAT3 pathway by stimulating VEGFR2 and STAT3 nuclear translocation in the presence of importin-β. Our research offer a new insight into the potential molecular mechanisms in which PBM promotes angiogenesis in wound healing.

The effect of photomodulation on fibroblast growth factor and the Ras/MAPK signalling pathway: a review

Objective:

Current therapies and technologies used to treat hard-to-heal diabetic wounds are limited to a 50% healing rate. The rise in the percentage of lower limb non-traumatic amputations in patients with diabetes has caused an increased demand for alternative, effective and safe treatment modalities. Photobiomodulation therapy (PBMT) utilises light to induce physiological changes and provide therapeutic benefits and has been shown to increase the healing of hard-to-heal wounds through the release of growth factors. The aim of this narrative review is to investigate the effect of photobiomodulation (PBM) on fibroblast growth factor (FGF) and the role of the Ras/MAPK signalling pathway in diabetic wound healing.

Method:

Relevant journal articles were obtained through PubMed and Google Scholar.

Results:

Experimental and clinical findings from the review show that PBM can stimulate the release of growth factors, including FGF, an essential cytokine in wound healing, and one which is present at lower concentrations in diabetic wounds. There is also activation of the Ras/MAPK signalling pathway.

Conclusion:

One mechanism through which healing may be stimulated by PBM is via the FGF-Ras/MAPK signalling pathway, although strong evidence under hyperglycaemic conditions is lacking.

Cardiac autonomic activity, endothelial function and physical fitness in type 2 diabetic patients

Objective: To investigate the association between cardiac autonomic activity, endothelial function, and physical fitness in patients with type 2 diabetes mellitus (T2DM). Methods: Twenty-seven patients with T2DM were studied, with a mean age of 57 ± 9 years and a mean disease duration of 7.4 ± 5 years. The assessment of physical fitness was performed using the Shuttle Walking Test (SWT), cardiac autonomic modulation by heart rate variability (HRV), and endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery through ultrasound imaging. Results: The main finding of this study was that some HRV indices (SDNN, RMSSD, and HF) were significantly correlated with endothelial function in individuals with T2DM, with R values between 0.51 and 0.57 (p < 0, 05), for all relationships. Additionally, an association was found between the distance covered in the SWT and the basal diameter of the brachial artery (R = 0.59; p = 0.01). Conclusion: Our data demonstrate that some HRV indices are associated with DMF, indicating an interaction between these two systems. Furthermore, our findings suggest a correlation between physical fitness and endothelial function in individuals with T2DM.

Photobiomodulation Therapy as a Possible New Approach in COVID-19: A Systematic Review

COVID-19 is a viral disease characterized as a pandemic by the World Health Organization in March 2020. Since then, researchers from all over the world have been looking for ways to fight this disease. Many cases of complications arise from insufficient immune responses due to low immunity, with intense release of pro-inflammatory cytokines that can damage the structure of organs such as the lung. Thus, the hypothesis arises that photobiomodulation therapy (PBMT) with the use of a low-level laser (LLLT) may be an ally approach to patients with COVID-19 since it is effective for increasing immunity, helping tissue repair, and reducing pro-inflammatory cytokines. This systematic review was performed with the use of PubMed/MEDLINE, Web of Science, Scopus and Google Scholar databases with the following keywords: "low-level laser therapy OR photobiomodulation therapy AND COVID-19". The inclusion criteria were complete articles published from January 2020 to January 2021 in English. The exclusion criteria were other languages, editorials, reviews, brief communications, letters to the editor, comments, conference abstracts, and articles that did not provide the full text. The bibliographic search found 18 articles in the Pubmed/MEDLINE database, 118 articles on the Web of Science, 23 articles on Scopus, and 853 articles on Google Scholar. Ten articles were included for qualitative synthesis, of which four commentary articles discussed the pathogenesis and the effect of PBMT in COVID-19. Two in vitro and lab experiments showed the effect of PBMT on prevention of thrombosis and positive results in wound healing during viral infection, using the intravascular irradiation (ILIB) associated with Phthalomethyl D. Two case reports showed PBMT improved the respiratory indexes, radiological findings, and inflammatory markers in severe COVID-19 patients. One case series reported the clinical improvement after PBMT on 14 acute COVID-19 patients, rehabilitation on 24 patients, and as a preventive treatment on 70 people. One clinical trial of 30 patients with severe COVID-19 who require invasive mechanical ventilation, showed PBMT-static magnetic field was not statistically different from placebo for the length of stay in the Intensive Care Unit, but improved diaphragm muscle function and ventilation and decreased the inflammatory markers. This review suggests that PBMT may have a positive role in treatment of COVID-19. Still, the necessity for more clinical trials remains in this field and there is not sufficient research evidence regarding the effects of PBMT and COVID-19 disease, and there is a large gap.

Biological Responses of Stem Cells to Photobiomodulation Therapy

BACKGROUND

Stem cells have attracted the researchers interest, due to their applications in regenerative medicine. Their self-renewal capacity for multipotent differentiation, and immunomodulatory properties make them unique to significantly contribute to tissue repair and regeneration applications. Recently, stem cells have shown increased proliferation when irradiated with low-level laser therapy or Photobiomodulation Therapy (PBMT), which induces the activation of intracellular and extracellular chromophores and the initiation of cellular signaling. The purpose of this study was to evaluate this phenomenon in the literature.

METHODS

The literature investigated the articles written in English in four electronic databases of PubMed, Scopus, Google Scholar and Cochrane up to April 2019. Stem cell was searched by combining the search keyword of "low-level laser therapy" OR "low power laser therapy" OR "low-intensity laser therapy" OR "photobiomodulation therapy" OR "photo biostimulation therapy" OR "LED". In total, 46 articles were eligible for evaluation.

RESULTS

Studies demonstrated that red to near-infrared light is absorbed by the mitochondrial respiratory chain. Mitochondria are significant sources of reactive oxygen species (ROS). Mitochondria play an important role in metabolism, energy generation, and are also involved in mediating the effects induced by PBMT. PBMT may result in the increased production of (ROS), nitric oxide (NO), adenosine triphosphate (ATP), and cyclic adenosine monophosphate (cAMP). These changes, in turn, initiate cell proliferation and induce the signal cascade effect.

CONCLUSION

The findings of this review suggest that PBMT-based regenerative medicine could be a useful tool for future advances in tissue engineering and cell therapy.

Experimental and Clinical Applications of Red and Near-Infrared Photobiomodulation on Endothelial Dysfunction: A Review

BACKGROUND

Under physiological conditions, endothelial cells are the main regulator of arterial tone homeostasis and vascular growth, sensing and transducing signals between tissue and blood. Disease risk factors can lead to their unbalanced homeostasis, known as endothelial dysfunction. Red and near-infrared light can interact with animal cells and modulate their metabolism upon interaction with mitochondria's cytochromes, which leads to increased oxygen consumption, ATP production and ROS, as well as to regulate NO release and intracellular Ca²⁺ concentration. This medical subject is known as photobiomodulation (PBM). We present a review of the literature on the in vitro and in vivo effects of PBM on endothelial dysfunction.

METHODS

A search strategy was developed consistent with the PRISMA statement. The PubMed, Scopus, Cochrane, and Scholar electronic databases were consulted to search for in vitro and in vivo studies.

RESULTS

Fifty out of >12,000 articles were selected.

CONCLUSIONS

The PBM can modulate endothelial dysfunction, improving inflammation, angiogenesis, and vasodilatation. Among the studies, 808 nm and 18 J (0.2 W, 2.05 cm²) intracoronary irradiation can prevent restenosis as well as 645 nm and 20 J (0.25 W, 2 cm²) can stimulate angiogenesis. PBM can also support hypertension cure. However, more extensive randomised controlled trials are necessary.

The effect of low-level laser therapy on diabetic foot ulcers: A meta-analysis of randomised controlled trials

Our purpose was to perform a meta‐analysis to evaluate the effect of Low‐level laser therapy (LLLT) on diabetic foot ulcers (DFUs). The PubMed, Cochrane, Embase, Web of Science, Chinese BioMedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), VIP and Wanfang databases were searched systematically up to August 27, 2020. Studies that met the inclusion criteria were included in the analysis. A total of 13 randomised controlled trials (RCTs) and 413 patients were analysed. Compared with the control group, LLLT significantly increased the complete healing rate (risk ratio [RR] = 2.10, 95% confidence interval [CI] 1.56‐2.83, P < .00001), reduced the ulcer area (standardised mean difference [SMD] = 3.52, 95% CI 1.65‐5.38, P = .0002), and shortened the mean healing time (SMD = −1.40, 95% CI −1.90 to −0.91, P < .00001) of patients with DFUs. The quality of the evidence was very low according to the GRADE system. LLLT is a promising and effective adjuvant treatment to accelerate the healing of DFUs. Further evidence from larger samples and higher quality RCTs is needed to prove the effect of LLLT and to determine the most appropriate parameters for the healing of DFUs.

Effects of Low Level Laser Therapy (LLLT) on Serum Values of Interleukin 6 (IL-6) in Patients with Periodontitis and Type 2 Diabetes Mellitus (T2DM)

BACKGROUND

In patients with T2DM, the therapeutic effects of conservative treatment are quite limited, and there is a need for additional therapeutic procedures to achieve the desired satisfactory and solid effect. Low-level laser therapy (LLLT) has an anti-inflammatory effect, and is used to heal lesions. This mechanism is realized through inhibition of lipopolysaccharides (LPS), so it can be used in the treatment of periodontal disease in patients with diabetes.

OBJECTIVE

The aim of this study is to assess the effect of level laser therapy (LLLT) on serum IL-6 values in patients with periodontitis and T2DM.

METHODS

Patients at age between 35-60 years old, with chronic periodontitis (CH) where the clinical loss of attachment (CAL) was ≥4 mm therefore covering at least 50 % of affected teeth. In this study we included 80 patients, divided into two groups: 40 patients with type 2 diabetes mellitus (2TDM) treated with conservative periodontal treatment supplemented with laser therapy (LLLT), group A, and 40 patients with 2TDM, conservatively treated without LLLT. therapy i.e. group B. The laser light was applied to the gingiva in separate quadrants in 5 sessions for the next five days in a row. Blood samples were taken from all subjects at the first treatment, then in 6 weeks and 3 months after treatment, and interleukin 6 (IL-6) levels were measured. The blood samples in the test tubes remained for about 30 minutes and were then distributed in a biochemical laboratory, where they were centrifuged at 6,000 rpm for 10 minutes. The serum was separated from the test tube and transferred to the eppendorph. All serum samples were stored at -80 ° C until complete analysis and determination of IL-6, according to the standardized methodology.

RESULTS

In group A, on the first examination serum IL-6 levels varies in the interval 11.54 ± 1.11 pg / mL, after 6 weeks of therapy the values range between 11.26 ± 0.77 pg / mL, and after 3 months of therapy levels oscillate at intervals of 11.02 ± 0.67 pg / mL. In group B the findings are similar. At the first examination, the serum IL-6 values were 11.56 ± 0.81 pg / mL, after 6 weeks of therapy ranged from 11.59 ± 0.71 pg / mL, and after 3 months of therapy levels were recorded at intervals. 11.41 ± 0.78 pg /mL. The serum IL-6 value after 6 weeks of therapy in patients in group B for Z = -2.04 and p <0.05 (p = 0.04) was significantly higher than in patients in group A, while after 3 months of therapy in patients in group B for Z = -2.42 and p <0.05 (p = 0.02) is significantly higher than the value in patients in group A.

CONCLUSION

LLLT resulted in significantly reduced serum IL-6 values in patients with periodontitis and T2DM after 6 weeks and 3 months of therapy in which conservative treatment was supplemented with LLLT.

Effect of 660/850 nm LED on the microcirculation of the foot: neurovascular biphasic reflex

Phototherapy (LED) can be used to stimulate the healing of chronic ulcers of the lower limb, as it affects healing cells and neurons. In this way, this study has sought to know if the heat stimulus of the 660-/850-nm contact LED is sufficient to trigger the response in the peripheral sympathetic nervous system of normal volunteers. The LED was applied on the right foot of forty-two normal volunteers followed by serial infrared images. After the stimulus, a biphasic hyperthermia curve was observed synchronously in both feet, in the right and left halluxes, while hyperthermia was attributed to the redistribution of postural blood flow in the plantar region, which may indicate independent neurovascular mechanisms. Thus, periodic thermographic analysis can be used in the evolution of the LED treatment.

Proposed mechanisms of low-level light therapy in the treatment of androgenetic alopecia

Androgenetic alopecia (AGA) is a global challenge, affecting a large number of people worldwide. Efficacy of the existed treatments can barely meet the demands of patients. Patients who are poorly responding to those treatments are seeking for a more effective and suitable technique to treat their disease. Low-level light therapy (LLLT) is a newly developed technique, which has been proved to stimulate hair growth. Based on the function principle of LLLT in other domains and refer to the published literatures, we write this review to neaten and elucidate the possible mechanism of LLLT in the treatment of AGA. A review of published literature which is associated with keywords LLLT, photobiomodulation, AGA, treatment, hair growth, and mechanism was performed to elucidate the proposed mechanism of LLLT in the treatment of AGA. The present study shows that LLLT can accelerate hair growth in AGA patients. The proposed mechanism of LLLT in treating AGA may vary among different specialists. But we can summarize the consensual mechanisms as follows; low-level light absorbed by chromophores can lead to the production of nitric oxide (NO) and the modulation of reactive oxygen species (ROS). These mobilized molecules subsequently activate redox-related signaling pathways in hair follicle cells and perifollicular cells. Finally, these activated cells participate in the regrowth of hair follicle. Even though the efficacy of LLLT in the treatment of AGA in both men and women has already been confirmed, the present studies focusing on discovering LLLT are still inadequate and unsystematic. More studies are needed to standardize the optimum treatment parameters applied in promoting hair growth and determine the long-term safety and efficacy of LLLT. Current recognitions about the mechanisms of LLLT, mainly focused on the molecules that may take effect, neglected different cellular components that are functional in the hair follicle macro-environment.

Photobiomodulation alters the viability of HUVECs cells

The aim of the present study was to investigate the influence of low-level red (660 nm) and infrared (780 nm) laser with four different radiance exposures on human umbilical vein endothelial cells (HUVECs) in vitro. HUVECs (1.5 × 10⁴) were incubated in 96-well culture plates. The cells were maintained in M199 medium supplemented with 20% fetal bovine serum, 1% antibiotic (penicillin), 1% anti-mycotic (Fungizone), and 1% endothelial cell growth supplement. After centrifugation, irradiations (660/780 nm, 40 mW, 1, 5, 10, and 20 J/cm², 1 s, 5 s, 10 s, and 20 s, respectively, total energy 0.4 J, 2 J, 4 J, and 8 J, and beam spot size at target 0.04 cm²) were performed at the bottom of Falcon tubes such that the laser beam directly reached the cell without passing through the culture medium. The cells were divided into groups based on radiant exposures. Cell viability and protein concentration were verified after 1, 2, 3, 6, 8, and 10 days. Red laser increased the cell viability and protein concentration in all groups (three-way ANOVA, p < 0.05) beginning on the second day. The greatest peak compared with the control was found when the radiant exposure was 5 J/cm² and 10 J/cm². Infrared laser inhibited cell viability and modulated the protein concentration in the cells, with the highest peak protein concentration found on the second day in the group with radiant exposure of 1 J/cm² and 10 J/cm² (three-way ANOVA, p < 0.05). Red laser increased the viability and concentration of total proteins in HUVECs, whereas infrared laser had an inhibitory effect on cell viability, while maintaining the total protein concentration similar to that found in the control group.

The effects of humic water on endothelial cells under hyperglycemic conditions: inflammation-associated parameters

Humic waters (HW) are globally unique, deep underground, dark-brown waters containing humic acids, and they present numerous therapeutic activities including anti-inflammatory. In the present study, we use HW from source in Poland. Diabetes has become an epidemic and is a risk factor of cardiovascular diseases. Hyperglycemia in diabetes is responsible for damaging of the endothelium and increases inflammation on the surface of the vascular lining. The inflammatory process in diabetes is associated with the secretion of inflammatory cytokines by endothelial cells, e.g., tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6), and with the reduction of cell proliferation. In the study, we used cultures of endothelial cells (HUVEC line-human umbilical vein endothelial cells) with the addition 30 mM/L of glucose in the culture medium which imitated the conditions of uncontrolled diabetes. The addition of HW in the proper volume to the culture medium causes reduction of inflammation by significant decrease in inflammatory cytokines such as TNFα and IL-6 and also leads to enhancement of the cell proliferation. It appears that the adverse effects of hyperglycemia on vascular endothelial cells may be corrected by addition of humic water. The above promising results of in vitro tests provide an opportunity to the possible use of humic water in the supportive treatment of endothelial dysfunction disorders in diabetes. However, this issue requires further clinical research.

Efficacy of Biophysical Energies on Healing of Diabetic Skin Wounds in Cell Studies and Animal Experimental Models: A Systematic Review

We have systematically assessed published cell studies and animal experimental reports on the efficacy of selected biophysical energies (BPEs) in the treatment of diabetic foot ulcers. These BPEs include electrical stimulation (ES), pulsed electromagnetic field (PEMF), extracorporeal shockwave (ECSW), photo energies and ultrasound (US). Databases searched included CINAHL, MEDLINE and PubMed from 1966 to 2018. Studies reviewed include animal and cell studies on treatment with BPEs compared with sham, control or other BPEs. Information regarding the objective measures of tissue healing and data was extracted. Eighty-two studies were eventually selected for the critical appraisal: five on PEMF, four each on ES and ECSW, sixty-six for photo energies, and three about US. Based on the percentage of original wound size affected by the BPEs, both PEMF and low-level laser therapy (LLL) demonstrated a significant clinical benefit compared to the control or sham treatment, whereas the effect of US did not reveal a significance. Our results indicate potential benefits of selected BPEs in diabetic wound management. However, due to the heterogeneity of the current clinical trials, comprehensive studies using well-designed trials are warranted to confirm the results.

Effects of near infrared focused laser on the fluorescence of labelled cell membrane

Near infrared (NIR) laser light can have important reactions on live cells. For example, in a macroscopic scale, it is used therapeutically to reduce inflammation and in a single-cell scale, NIR lasers have been experimentally used to guide neuronal growth. However, little is known about how NIR lasers produce such behaviours on cells. In this paper we report effects of focussing a continuous wave 810-nm wavelength laser on in vivo 3T3 cells plasma membrane. Cell membranes were labelled with FM 4-64, a dye that fluoresces when associated to membrane lipids. Confocal microscopy was used to image cell membranes and perform fluorescence recovery after photobleaching (FRAP) experiments. We found that the NIR laser produces an increase of the fluorescence intensity at the location of laser spot. This intensity boost vanishes once the laser is turned off. The mean fluorescence increase, calculated over 75 independent measurements, equals 19%. The experiments reveal that the fluorescence rise is a growing function of the laser power. This dependence is well fitted with a square root function. The FRAP, when the NIR laser is acting on the cell, is twice as large as when the NIR laser is off, and the recovery time is 5 times longer. Based on the experimental evidence and a linear fluorescence model, it is shown that the NIR laser provokes a rise in the number of molecular associations dye-lipid. The results reported here may be a consequence of a combination of induced increments in membrane fluidity and exocytosis.

Role of photobiomodulation on the activation of the Smad pathway via TGF-β in wound healing

Wound healing is an essential process in which the separated or destroyed tissue attempts to restore itself into its normal state. In some instances, healing is prolonged and remains stagnant in the inflammatory phase, and is referred to as a chronic wound. At a cellular and molecular level, many factors are required during the process of successful wound healing, such as cytokines, polypeptide growth factors and components of the extracellular matrix (ECM). Transforming growth factor-beta (TGF-β) is considered as one of the essential growth factors in wound healing. Working through the Smad pathway, it is the main inducer of fibroblast differentiation which is essential for wound healing. Photobiomodulation (PBM) shows significant advantages in wound healing, and may stimulate cellular processes and tissue regeneration that results in an increase in growth factors and a decrease in inflammatory cytokines. Moreover, it leads to enhanced cell proliferation, migration, angiogenesis, and increased adenosine triphosphate (ATP) and cytochrome C oxidase (CCO) activity. In this review paper, we discuss the effects of PBM and its role on the activation of the TGF-β/Smad pathway in the process of wound healing.

Low-level laser irradiation modifies the effect of hyperglycemia on adhesion molecule levels

Endothelium plays a key role in maintaining vascular homeostasis by secreting active factors involved in many biological processes such as hemostasis, angiogenesis, and inflammation. Hyperglycemia in diabetic patients causes dysfunction of endothelial cells. Soluble fractions of adhesion molecules like sE-selectin and vascular cell adhesion molecule (sVCAM) are considered as markers of endothelial damage. The low-level laser therapy (LLLT) effectively supports the conventional treatment of vascular complications in diabetes, for example hard-to-heal wounds in patients with diabetic foot syndrome. The aim of our study was to evaluate the effect of low-energy laser at the wavelength of 635 nm (visible light) and 830 nm (infrared) on the concentration of adhesion molecules: sE-selectin and sVCAM in the supernatant of endothelial cell culture of HUVEC line. Cells were cultured under high-glucose conditions of 30 mM/L. We have found an increase in sE-selectin and sVCAM levels in the supernatant of cells cultured under hyperglycemic conditions. This fact confirms detrimental influence of hyperglycemia on vascular endothelial cell cultures. LLLT can modulate the inflammation process. It leads to a decrease in sE-selectin and sVCAM concentration in the supernatant and an increase in the number of endothelial cells cultured under hyperglycemic conditions. The influence of LLLT is greater at the wavelength of 830 nm.

Cell Adhesion Molecules are Mediated by Photobiomodulation at 660 nm in Diabetic Wounded Fibroblast Cells

Diabetes affects extracellular matrix (ECM) metabolism, contributing to delayed wound healing and lower limb amputation. Application of light (photobiomodulation, PBM) has been shown to improve wound healing. This study aimed to evaluate the influence of PBM on cell adhesion molecules (CAMs) in diabetic wound healing. Isolated human skin fibroblasts were grouped into a diabetic wounded model. A diode laser at 660 nm with a fluence of 5 J/cm² was used for irradiation and cells were analysed 48 h post-irradiation. Controls consisted of sham-irradiated (0 J/cm²) cells. Real-time reverse transcription (RT) quantitative polymerase chain reaction (qPCR) was used to determine the expression of CAM-related genes. Ten genes were up-regulated in diabetic wounded cells, while 25 genes were down-regulated. Genes were related to transmembrane molecules, cell–cell adhesion, and cell–matrix adhesion, and also included genes related to other CAM molecules. PBM at 660 nm modulated gene expression of various CAMs contributing to the increased healing seen in clinical practice. There is a need for new therapies to improve diabetic wound healing. The application of PBM alongside other clinical therapies may be very beneficial in treatment.