Laser and LED phototherapies on angiogenesis

Comparative Effectiveness of Diode Laser Therapy and Topical Turmeric Extract Ointment in Promoting Healing of Wounds in a Murine Model

The intricate biological process of wound healing is influenced by a wide range of therapeutic techniques. In this work, the effects of topical turmeric extract ointment and diode laser therapy on wound healing in a mouse model were investigated. Out of the sixty mice, three groups of twenty male mice each were created. Three groups received treatment: the first was a control group that got no treatment; the second group received topical application of 5% curcumin twice a day; and the third group received diode laser therapy, which involved direct laser beam therapy for five minutes a day at an output power of 100 mW at an 810 nm wavelength. Over the course of two weeks, the study examined histological changes and wound closure rates. On days 0 through 14, the wound area was measured with digital calipers to provide quantifiable statistics about the process of healing. In histological analyses, epithelializations, and collagen deposition, in addition to inflammatory cells, were investigated using hematoxylin and eosin staining. It was demonstrated by comparing the outcomes to those of a control group that diode laser therapy and turmeric extract ointment are both successful therapeutic options. The results demonstrate that different therapies, while with differing degrees of effectiveness, greatly quicken the healing process of wounds. According to these results, topical turmeric extract ointment could be used as an additional or supporting therapy to aid in the healing of wounds during medical treatments.

Radioreparative Effect of Diode Laser on Leukopoiesis Recovery: A Pilot Study

The aim of the present study was to investigate the effect of laser therapy on leukopoiesis recovery after irradiation with ionizing radiation. A dose of ionizing radiation was used that induced the hematological form of radiation sickness, reducing the number of blood cells. Subsequently, mice were treated with non-ionizing laser radiation. Based on the examination of the peripheral blood, the study found that laser therapy significantly impacted the number of eosinophils and basophils two weeks after irradiation. Laser therapy also led to the faster reparation of the lymphocyte lineage of white blood cells (WBCs). The research showed that the examined therapeutic laser had a long-term radioreparative effect on gamma-irradiated mice, improving the absolute counts of different lines of WBCs. The results of this study could have implications for the treatment of radiation sickness in humans.

Effects of photobiomodulation with blue Light Emitting Diode (LED) on the healing of skin burns

The management of skin burns is still challenging. Among the therapeutic methods used, there are topical treatments with pharmacological and herbal agents, low-intensity therapeutic ultrasound, use of biomaterials, reconstructive techniques and photobiomodulation therapy. The aim of this study was to evaluate the effects of photobiomodulation with blue Light Emitting Diode (LED) on burn healing. Fifty Wistar rats were divided into control (CTRL) (n = 25) and blue LED (LED) (n = 25), with subgroups (n = 5) for each time of euthanasia (7, 14, 21, 28 and 32 days). Treated animals were daily irradiated (470 nm, 1W, 0.44 W/cm2, 50 J/cm2). Clinical evaluations were performed and the Wound Retraction Index (WRI) was determined. Histological sections were submitted to hematoxylin-eosin, toluidine blue and the immunohistochemical technique, with anti-α-SMA and anti-TGF-β1 antibodies. All data were directly collected by previously calibrated evaluators in a blind manner. The values were included in a statistical program. For all statistical tests used, 5% significance level (p < 0.05) was considered. No statistically significant differences in WRI between groups were observed (p > 0.05). Re-epithelialization was higher using LED at 7 and 14 days (p < 0.05) and greater amount of inflammatory cells was observed at 7 days (p = 0.01). With LED at 21 and 32 days, greater number of mast cells were observed (p < 0.05), as well as smaller number of myofibroblasts at 14, 21, 28 and 32 days (p < 0.05) and lower percentage of TGF-β1 positive cells in the conjunctiva at 7, 14 and 21 days (p < 0.05). Negative correlations were observed in LED between the percentage of TGF-β1 in the epithelium and the mean number of inflammatory cells and number of myofibroblasts (p < 0.05). The results suggest that, depending on the period, blue LED can modulate the healing processes of third-degree skin burns, such as re-epithelialization, inflammatory response, mast cell concentration, myofibroblast differentiation and TGF-β1 immunoexpression. Despite these effects, this therapy does not seem to have significant influence on the retraction of these wounds. Future studies, using different protocols, should be carried out to expand the knowledge about the photobiomodulatory mechanisms of this type of light in the healing process.

Effects of photobiomodulation therapy with red LED on inflammatory cells during the healing of skin burns

The aim of this study was to evaluate the effects of red light emitting diode (LED) photobiomodulation therapy protocol on inflammatory cells during the healing of third-degree skin burns. Fifty Wistar rats were randomly divided into control group (CTRL) (n = 25) and red group (RED) (n = 25), with subgroups (n = 5) for each time of euthanasia (7, 14, 21, 28, and 32 days). Treatment animals were daily irradiated (630 nm ± 10 nm, 300 mW, 9 J/cm² per point, 30 s, continuous emission mode) at the 4 angles of the wound (total: 36 J/cm²). After specimen removal, histological sections were stained with hematoxylin and eosin for quantitative analysis of the inflammatory infiltrate (neutrophils and lymphocytes) under light microscopy. Greater number of inflammatory cells was observed in irradiated groups when compared to CTRL at 7, 14, 21, and 28 days, but with statistically significant difference only at 14 days (p = 0.02). At 32 days, higher inflammatory cell value was observed in CTRL when compared to RED, but with no statistically significant difference (p = 0.91). The results suggest that red LED, according to the protocol used, modulates the number of inflammatory cells in the early stages of the healing of third-degree skin burns. Nevertheless, this low-intensity light therapy may not, be efficient in reducing the number of neutrophils and lymphocytes in advanced stages of the repair process of skin burns. Further studies with other therapy protocols are needed to assess the effects of this type of light on the inflammatory response of skin burns.

Area light source-triggered latent angiogenic molecular mechanisms intensify therapeutic efficacy of adult stem cells

Light-based therapy such as photobiomodulation (PBM) reportedly produces beneficial physiological effects in cells and tissues. However, most reports have focused on the immediate and instant effects of light. Considering the physiological effects of natural light exposure in living organisms, the latent reaction period after irradiation should be deliberated. In contrast to previous reports, we examined the latent reaction period after light exposure with optimized irradiating parameters and validated novel therapeutic molecular mechanisms for the first time. we demonstrated an organic light-emitting diode (OLED)-based PBM (OPBM) strategy that enhances the angiogenic efficacy of human adipose-derived stem cells (hADSCs) via direct irradiation with red OLEDs of optimized wavelength, voltage, current, luminance, and duration, and investigated the underlying molecular mechanisms. Our results revealed that the angiogenic paracrine effect, viability, and adhesion of hADSCs were significantly intensified by our OPBM strategy. Following OPBM treatment, significant changes were observed in HIF-1α expression, intracellular reactive oxygen species levels, activation of the receptor tyrosine kinase, and glycolytic pathways in hADSCs. In addition, transplantation of OLED-irradiated hADSCs resulted in significantly enhanced limb salvage ratio in a mouse model of hindlimb ischemia. Our OPBM might serve as a new paradigm for stem cell culture systems to develop cell-based therapies in the future.

Fluorescent light energy modulates healing in skin grafted mouse model

Skin grafting is often the only treatment for skin trauma when large areas of tissue are affected. This surgical intervention damages the deeper dermal layers of the skin with implications for wound healing and a risk of scar development. Photobiomodulation (PBM) therapy modulates biological processes in different tissues, with a positive effect on many cell types and pathways essential for wound healing. This study investigated the effect of fluorescent light energy (FLE) therapy, a novel type of PBM, on healing after skin grafting in a dermal fibrotic mouse model. Split-thickness human skin grafts were transplanted onto full-thickness excisional wounds on nude mice. Treated wounds were monitored, and excised xenografts were examined to assess healing and pathophysiological processes essential for developing chronic wounds or scarring. Results demonstrated that FLE treatment initially accelerated re-epithelialization and rete ridge formation, while later reduced neovascularization, collagen deposition, myofibroblast and mast cell accumulation, and connective tissue growth factor expression. While there was no visible difference in gross morphology, we found that FLE treatment promoted a balanced collagen remodeling. Collectively, these findings suggest that FLE has a conceivable effect at balancing healing after skin grafting, which reduces the risk of infections, chronic wound development, and fibrotic scarring.

Electric Factors in Wound Healing

Significance: Electric factors such as electric charges, electrodynamic field, skin battery, and interstitial exclusion permeate wound healing physiology and physiopathology from injury to re-epithelialization. The understanding of how electric factors contribute to wound healing and how treatments may interfere with them is fundamental for the development of better strategies for the management of pathological scarring and chronic wounds. Recent Advances: Angiogenesis, cell migration, macrophage activation hemorheology, and microcirculation can interfere and be interfered with electric factors. New treatments with various types of electric currents, laser, light emitting diode, acupuncture, and weak electric fields applied directly on the wound have been developed to improve wound healing. Critical Issues: Despite the basic and clinical development, pathological scars such as keloids and chronic wounds are still a challenge. Future Directions: New treatments can be developed to improve skin wound healing taking into account the influence of electrical charges. Monitoring electrical activity during skin healing and the influence of treatments on hemorheology and microcirculation are examples of how to use knowledge of electrical factors to increase their effectiveness.

Benefits of Sebastiania hispida (Euphorbiaceae) extract and photobiomodulation therapy as potentially adjunctive strategies to be explored against snake envenoming

The purpose of this study was to assess the topic use of Sebastiania hispida extract and low-level gallium-arsenide laser irradiation (GaAs, 904 nm) to reduce the local myonecrosis and edema of Bothrops moojeni snake venom-injected gastrocnemius. Wistar rats receiving intramuscular venom injection (VBm) were compared with saline control (S) and envenomed rats receiving local exposure to plant extract (VExt) or laser irradiation (VL). The phytochemistry and thin-layer chromatography of S. hispida extract indicated the presence of phenolic compounds like gallic acid and flavonoids including quercetin. Gastrocnemius of VExt and VL groups had a significant reduction of edema and creatine kinase (CK) activities and a greater Myogenin (MyoG) expression compared to VBm group, with the plant extract efficacy better than laser exposure. Reduction of edema and serum CK activities reflects a lessening of muscle damage, whereas the increase of MyoG indicates myoblast differentiation and acceleration of muscle repair. The S. hispida richness in phenolic compounds and flavonoids, such as the light modulatory ability to triggering a multitude of cell signalings likely underlie the positive outcomes. Our findings suggest both treatments as potential auxiliary tools to be explored in clinical trials in combination with anti-venom therapy after Bothropic snakebites.

The impact of photobiomodulation on the chondrogenic potential of adipose-derived stromal/stem cells

Due to their capacity to differentiate into the chondrogenic lineage, adipose-derived stromal/stem cells (ASC) are a promising source of therapeutically relevant cells for cartilage tissue regeneration. Their differentiation potential, however, varies between patients. In our study, we aim to stimulate ASC towards a more reliable chondrogenic phenotype using photobiomodulation (PBM). LED devices of either blue (475 nm), green (516 nm) or red (635 nm) light were used to treat human ASC from donors of varying chondrogenic potential. The treatment was applied either once during the 2D expansion phase or repeatedly during the 3D differentiation phase. Chondrogenic differentiation was assessed via pellet size, GAG/DNA content, histology and gene expression analysis. Reactions to PBM were found to be wavelength-dependent and more pronounced when the treatment was applied during expansion. Donors were assigned to responder categories according to their response to the treatment during expansion, whereby good responders were mainly donors with low intrinsic chondrogenic potential. Exposed to light, they revealed a particularly high relative increase in pellet size (more than twice the size of untreated controls after red light PBM), intense collagen type II immunostaining (low/absent in untreated controls) and activation of otherwise absent COL2A1 expression. Conversely, on a donor with high intrinsic chondrogenic potential, light had adverse effects. When applied with shorter wavelengths (blue, green), it led to reduced pellet size, GAG/DNA content and collagen type II immunostaining. However, when PBM was applied in 3D, the same donor was the only one to react with increased differentiation to all three wavelengths. We were able to demonstrate that PBM can be used to enhance or hamper chondrogenesis of ASC, and that success depends on treatment parameters and intrinsic cellular potential. The improvement of chondrogenesis in donors with low intrinsic potential highlights PBM as potent tool for cell-based cartilage regeneration. Its cost-effectiveness and ease of use make for an attractive treatment option to enhance the performance of ASC in cartilage tissue engineering.

Photobiomodulation-blue and red LED: protection or cellular toxicity? In vitro study with human fibroblasts

Photobiomodulation is widely used in clinical practice, and there is increasing interest in using this tool to treat numerous dysfunctions in living organisms. Therefore, this study aimed to verify the action of blue and red light-emitting diode light in cells. Human fibroblast cell line (HFF-1) were irradiated by blue (470 nm) or red (658 nm) light at doses of 4 and 18 J/cm², respectively. Laboratory analyses were carried out to check for viability, proliferation, cell death, and the formation of reactive oxygen and nitric oxide species. The blue light demonstrated cell protection potential by reducing free radical formation and protecting the cell membrane by decreasing double-stranded DNA strands. On the other hand, the red light showed less potential for cell protection due to the risk of associating more significant nitric oxide formation with increased reactive oxygen species formation, in addition to having a greater amount of extracellular DNA. Cell damage prevention is a potential beneficial effect of blue light at 18 J/cm². Despite the consolidated effects of red light in treating wounds, there was a potential toxic effect of this wavelength in the doses studied. Given the above, new studies relating these parameters with pathological cells or aggressors that simulate damage may offer results that can better support clinical practice.

Patient Centeredness in Orthognathic Surgery

Patient centeredness in planning treatment and research has become paramount. The goal of this report was to describe a complex case in which untreated chronic pain was not properly addressed to reflect on the need to establish alternative protocols for controlling chronic orofacial pain. When a female underwent orthognathic surgery to correct her occlusion, she not only ended up with a worse occlusion, she developed chronic orofacial pain that could not be treated by opioids and only improved after the use of neuropathic medication, and finally disappeared after the use of low-level laser therapy. There is a need to incorporate alternative nonpharmacological approaches to manage chronic pain. Further, what the patient’s goals are for their treatments should be given priority in case of elective procedures.

Synergistic effect of three-dimensional coculture and photobiomodulation therapy on vascularized liver spheroid formation by stem cells

Despite studies reporting functional differentiation of liver cells, a three-dimensional, vascularized liver organ has yet to be developed from mesenchymal stem cells. We investigated whether treatment with photobiomodulation (PBM) before three-dimensional liver spheroid transplantation improved the recovery of liver function via stimulation of angiogenesis and hepatocyte differentiation. Liver spheroids composed of hepatic, endothelial, and mesenchymal cells were subjected to PBM therapy. To evaluate the in vivo therapeutic effect of the liver spheroids treated with PBM, phosphate-buffered saline, liver spheroid, and PBM-treated liver spheroid were transplanted into a damaged host liver using conventional chimeric mouse models. To further characterize the maturation of transplanted PBM-liver spheroid compared with the newly generated non-PBM-liver spheroid or human liver tissues, the expression profiles of mature liver signature genes were analyzed. Liver spheroids expressed hepatocyte growth factors, including vascular endothelial growth factor and angiogenic factors. The cells in liver spheroid compensated for the low viability and improved the function of hepatocytes. Here, we demonstrate the formation of vascularized and functional human liver spheroid from human adipose-derived stem cells by transplantation of liver tissue created in vitro. Albumin secretion by PBM-treated liver spheroid was higher on Day 28 compared with liver spheroid-seeded transplant group. PBM-liver spheroids serve as individual vascularization units, promoting the simultaneous development of new microvascular networks at different locations inside the implanted tissue constructs. The vasculature in the liver spheroid transplants became functional by connecting to the host vessels within 48 h. These PBM-liver spheroids may be useful in designing artificial three-dimensional hepatic tissue constructs and in cell therapy with limited numbers of human hepatocytes.

Phototherapy as a Rational Antioxidant Treatment Modality in COVID-19 Management; New Concept and Strategic Approach: Critical Review

The COVID-19 pandemic has taken the entire globe by storm. The pathogenesis of this virus has shown a cytokine storm release, which contributes to critical or severe multi-organ failure. Currently the ultimate treatment is palliative; however, many modalities have been introduced with effective or minimal outcomes. Meanwhile, enormous efforts are ongoing to produce safe vaccines and therapies. Phototherapy has a wide range of clinical applications against various maladies. This necessitates the exploration of the role of phototherapy, if any, for COVID-19. This critical review was conducted to understand COVID-19 disease and highlights the prevailing facts that link phototherapy utilisation as a potential treatment modality for SARS-CoV-2 viral infection. The results demonstrated phototherapy's efficacy in regulating cytokines and inflammatory mediators, increasing angiogenesis and enhancing healing in chronic pulmonary inflammatory diseases. In conclusion, this review answered the following research question. Which molecular and cellular mechanisms of action of phototherapy have demonstrated great potential in enhancing the immune response and reducing host-viral interaction in COVID-19 patients? Therefore, phototherapy is a promising treatment modality, which needs to be validated further for COVID-19 by robust and rigorous randomised, double blind, placebo-controlled, clinical trials to evaluate its impartial outcomes and safety.

Light-emitting diode irradiation induces AKT/mTOR-mediated apoptosis in human pancreatic cancer cells and xenograft mouse model

The beneficial effects of light-emitting diode (LED) irradiation have been reported in various pathologies, including cancer. However, its effect in pancreatic cancer cells remains unclear. Herein, we demonstrated that blue LED of 460 nm regulated pancreatic cancer cell proliferation and apoptosis by suppressing the expression of apoptosis-related factors, such as mutant p53 and B-cell lymphoma 2 (Bcl-2), and decreasing the expression of RAC-β serine/threonine kinase 2 (AKT2), the phosphorylation of protein kinase B (AKT), and mammalian target of rapamycin (mTOR). Blue LED irradiation also increased the levels of cleaved poly-(ADP-ribose) polymerase (PARP) and caspase-3 in pancreatic cancer cells, while it suppressed AKT2 expression and inhibited tumor growth in xenograft tumor tissues. In conclusion, blue LED irradiation suppressed pancreatic cancer cell and tumor growth by regulating AKT/mTOR signaling. Our findings indicated that blue LEDs could be used as a nonpharmacological treatment for pancreatic cancer.

Under the spotlight: mechanisms of photobiomodulation concentrating on blue and green light

Photobiomodulation (PBM) describes the application of light at wavelengths ranging from 400-1100 nm to promote tissue healing, reduce inflammation and promote analgesia. Traditionally, red and near-infra red (NIR) light have been used therapeutically, however recent studies indicate that other wavelengths within the visible spectrum could prove beneficial including blue and green light. This review aims to evaluate the literature surrounding the potential therapeutic effects of PBM with particular emphasis on the effects of blue and green light. In particular focus is on the possible primary and secondary molecular mechanisms of PBM and also evaluation of the potential effective parameters for application both in vitro and in vivo. Studies have reported that PBM affects an array of molecular targets, including chromophores such as signalling molecules containing flavins and porphyrins as well as components of the electron transport chain. However, secondary mechanisms tend to converge on pathways induced by increases in reactive oxygen species (ROS) production. Systematic evaluation of the literature indicated 72% of publications reported beneficial effects of blue light and 75% reported therapeutic effects of green light. However, of the publications evaluating the effects of green light, reporting of treatment parameters was uneven with 41% failing to report irradiance (mW cm-2) and 44% failing to report radiant exposure (J cm-2). This review highlights the potential of PBM to exert broad effects on a range of different chromophores within the body, dependent upon the wavelength of light applied. Emphasis still remains on the need to report exposure and treatment parameters, as this will enable direct comparison between different studies and hence enable the determination of the full potential of PBM.

Photobiomodulation Enhances the Angiogenic Effect of Mesenchymal Stem Cells to Mitigate Radiation-Induced Enteropathy

Radiation-induced enteropathy remains a major complication after accidental or therapeutic exposure to ionizing radiation. Recent evidence suggests that intestinal microvascular damage significantly affects the development of radiation enteropathy. Mesenchymal stem cell (MSC) therapy is a promising tool to regenerate various tissues, including skin and intestine. Further, photobiomodulation (PBM), or low-level light therapy, can accelerate wound healing, especially by stimulating angiogenesis, and stem cells are particularly susceptible to PBM. Here, we explored the effect of PBM on the therapeutic potential of MSCs for the management of radiation enteropathy. In vitro, using human umbilical cord blood-derived MSCs, PBM increased proliferation and self-renewal. Intriguingly, the conditioned medium from MSCs treated with PBM attenuated irradiation-induced apoptosis and impaired tube formation in vascular endothelial cells, and these protective effects were associated with the upregulation of several angiogenic factors. In a mouse model of radiation-induced enteropathy, treatment with PBM-preconditioned MSCs alleviated mucosal destruction, improved crypt cell proliferation and epithelial barrier functions, and significantly attenuated the loss of microvascular endothelial cells in the irradiated intestinal mucosa. This treatment also significantly increased angiogenesis in the lamina propria. Together, we suggest that PBM enhances the angiogenic potential of MSCs, leading to improved therapeutic efficacy for the treatment of radiation-induced enteropathy.

Vascular Effects of Photodynamic Therapy with Curcumin in a Chorioallantoic Membrane Model

Photodynamic Therapy (PDT) is a treatment that requires light, a photosensitizing agent, and molecular oxygen. The photosensitizer is activated by light and it interacts with the oxygen that is present in the cellular microenvironment. The molecular oxygen is transformed into singlet oxygen, which is highly reactive and responsible for the cell death. Therefore, PS is an important element for the therapy happens, including its concentration. Curcumin is a natural photosensitizer and it has demonstrated its anti-inflammatory and anti-oxidant effects that inhibit several signal transduction pathways. PDT vascular effects of curcumin at concentrations varying from 0.1 to 10 mM/cm² and topical administration were investigated in a chick Chorioallantoic Membrane (CAM) model. The irradiation was performed at 450 nm, irradiance of 50 mW/cm² during 10 min, delivering a total fluence of 30 J/cm². The vascular effect was followed after the application of curcumin, with images being obtained each 30 min in the first 3 h, 12 h, and 24 h. Those images were qualitatively and quantitatively analyzed with a MatLAB®. Curcumin was expected to exhibit a vascular effect due to its angio-inhibitory effect. Using curcumin as photosensitizer, PDT induced a higher and faster vascular effect when compared to the use of this compound alone.

Improvement in infected wound healing in type 1 diabetic rat by the synergistic effect of photobiomodulation therapy and conditioned medium

We investigated the effects of photobiomodulation therapy (PBMT) and conditioned medium (CM) of human bone marrow mesenchymal stem cells (hBM-MSC) individually and/or in combination on the stereological parameters and the expression of basic fibroblast growth factor (bFGF), hypoxia-inducible factor (HIF-1α), and stromal cell-derived factor-1α (SDF-1α) in a wound model infected with methicillin-resistant Staphylococcus aureus (MRSA) in diabetic rats. CM was provided by culturing hBM-MSCs. Type 1 diabetes mellitus (T1DM) was induced in 72 rats, divided into four groups, harboring 18 rats each: group 1 served as a control group, group 2 received PBMT, group 3 received CM, and group 4 received CM + PBMT. On days 4, 7, and 15, six animals from each group were euthanized and the skin samples were separated for stereology examination and gene expression analysis by real-time polymerase chain reaction. In the CM + PBMT, CM, and PBMT groups, significant decreases were induced in the number of neutrophils (1460 ± 93, 1854 ± 138, 1719 ± 248) and macrophages (539 ± 69, 804 ± 63, 912 ± 41), and significant increases in the number of fibroblasts (1073 ± 116, 836 ± 75, 912 ± 41) and angiogenesis (15 230 ± 516, 13 318 ± 1116, 14 041 ± 867), compared with those of the control group (2690 ± 371, 1139 ± 145, 566 ± 90, 12 585 ± 1219). Interestingly, the findings of the stereological examination in the CM + PBMT group were statistically more significant than those in the other groups. In the PBMT group, in most cases, the expression of bFGF, HIF-1α, and SDF-1α, on day 4 (27.7 ± 0.14, 28.8 ± 0.52, 27.5 ± 0.54) and day 7 (26.8 ± 1.4, 29.6 ± 1.4, 28.3 ± 1.2) were more significant than those in the control (day 4, 19.3 ± 0.42, 25.5 ± 0.08, 22.6 ± 0.04; day 7, 22.3 ± 0.22, 28.3 ± 0.59, 24.3 ± 0.19) and other treatment groups. The application of PBMT + CM induced anti-inflammatory and angiogenic activities, and hastened wound healing process in a T1 DM model of MRSA infected wound.

Impact of low-level laser therapy on the dynamics of pressure ulcer-induced changes considering an infectious agent and cathelicidin LL-37 concentration: a preliminary study

INTRODUCTION

Low-level laser therapy is used in managing chronic wounds including pressure ulcers. Less is known about its impact on the healing process if an inhibitive agent e.g. bacterial infection takes place. Modulating non-specific immunity processes might eliminate bacteria if laser therapy is applied.

AIM

To investigate the impact of low-level laser therapy on pressure ulcer dynamics considering an infectious agent and cathelicidin LL-37 concentration.

MATERIAL AND METHODS

The study comprised 6 patients with pressure ulcers ranging from stage II to III in Torrance classification and 12 patients without pressure ulcers. Venous blood sample and decubitus wound swab were taken - in study groups A at baseline and after 2 weeks; in control group B once - at a specific point of time. The swabs served for species identification. Drug susceptibility of isolated pathogens and cathelicidin LL-37 in serum concentration were measured.

RESULTS

In study group A, the following bacteria predominantly occurred: S. aureus, E. faecalis, P. mirabilis, P. aeruginosa, while in control group B, excluding one MRSA case, S. hominis, S. epidermidis, D. nishinomiyaensis, A. haemolyticus (physiological flora) were present. HLGR resistance mechanisms were detected when analyzing drug susceptibility panels. Study group A findings demonstrated a statistically significant difference between the levels of cathelicidin LL-37 concentration at baseline and at the end.

CONCLUSIONS

There is insufficient information to accurately determine the effect of LLLT on pressure ulcer dynamics considering an infectious agent. These effects may occur if innate immunity processes are modulated so that laser therapy might eliminate bacteria indirectly.

Histopathological findings of an exposed human pulp carbonised by CO2 laser irradiation: A case report

This report shows the healing process of an exposed pulp carbonised by CO₂ laser irradiation prior to the application of a capping material. Six intact teeth from four volunteers were irradiated by CO₂ laser and randomly capped with either an adhesive resin (SE bond) (n = 3) or calcium hydroxide-based cement (Dycal) (n = 3). The laser was operated in super-pulsed mode (power output, 0.5 W) for an irradiation time of 30 s. All cavities were restored with composite resin. Each tooth was extracted at approximately 30, 50 or 260 days post treatment and prepared for histological evaluation. CO₂ laser irradiation controlled exudate and bleeding from each exposed pulp. Histological images revealed Dycal promoted complete dentine bridge formation at the carbonised pulp surface, and laser energy affected not only the pulp surface but also the deeper part of the pulp chamber.

Cardio-light: nitric oxide uncaged

Photobiomodulation (PB) is a utilization of low-level laser therapy (LLLT) in the far red (R) to near infrared (NIR) spectrum (600-1000 nm) to wield its therapeutic effects. To explore the therapeutic potential of biomodulation of different tissues, LLLT has been extensively researched, especially in the light of its very low side effect profile. We believe there is an opportunity to unearth its dynamic effects on the coronaries which can be promising for the patients with chronic stable angina. NIR treatment of the heart may be protective on patients after acute myocardial infarction or on ischemic heart conditions that are not accessible to current revascularization procedures.

Effect of blue LED on the healing process of third-degree skin burns: clinical and histological evaluation

The aim of this study was to evaluate the effects of blue light-emitting diode (LED) on the healing process of third-degree skin burns in rats through clinical and histological parameters. Forty male Wistar rats were divided into two groups: control (CTR) (n = 20) and blue LED (BLUE) (n = 20), with subgroups (n = 5) for each time of euthanasia (7, 14, 21, and 28 days). LED (470 nm, 1 W, 12.5 J/cm² per point, 28 s) was applied at four points of the wound (total, 50 J/cm²). Feed intake was measured every other day. It was observed that there were no statistically significant differences in the Wound Retention Index (WRI) of the BLUE group in relation to CTR group (p > 0.05) at the evaluation times. After 14, 21, and 28 days, it was observed that the animals in the BLUE group consumed more feed than animals in the CTR group (p < 0.05). At 7 days, there was a statistically significant increase in the angiogenic index (AI) in BLUE (median: 6.2) when compared to CTR (median: 2.4) (p = 0.01) and all animals in BLUE had already started re-epithelialization. This study suggests that blue LED, at the dosimetry used, positively contributed in important and initial stages of the healing process of third-degree skin burns.

Photobiomodulation: lasers vs. light emitting diodes?

Photobiomodulation (PBM) is a treatment method based on research findings showing that irradiation with certain wavelengths of red or near-infrared light has been shown to produce a range of physiological effects in cells, tissues, animals and humans. Scientific research into PBM was initially started in the late 1960s by utilizing the newly invented (1960) lasers, and the therapy rapidly became known as "low-level laser therapy". It was mainly used for wound healing and reduction of pain and inflammation. Despite other light sources being available during the first 40 years of PBM research, lasers remained by far the most commonly employed device, and in fact, some authors insisted that lasers were essential to the therapeutic benefit. Collimated, coherent, highly monochromatic beams with the possibility of high power densities were considered preferable. However in recent years, non-coherent light sources such as light-emitting diodes (LEDs) and broad-band lamps have become common. Advantages of LEDs include no laser safety considerations, ease of home use, ability to irradiate a large area of tissue at once, possibility of wearable devices, and much lower cost per mW. LED photobiomodulation is here to stay.

Photobiomodulation: lasers vs. light emitting diodes?

Photobiomodulation (PBM) is a treatment method based on research findings showing that irradiation with certain wavelengths of red or near-infrared light has been shown to produce a range of physiological effects in cells, tissues, animals and humans. Scientific research into PBM was initially started in the late 1960s by utilizing the newly invented (1960) lasers, and the therapy rapidly became known as "low-level laser therapy". It was mainly used for wound healing and reduction of pain and inflammation. Despite other light sources being available during the first 40 years of PBM research, lasers remained by far the most commonly employed device, and in fact, some authors insisted that lasers were essential to the therapeutic benefit. Collimated, coherent, highly monochromatic beams with the possibility of high power densities were considered preferable. However in recent years, non-coherent light sources such as light-emitting diodes (LEDs) and broad-band lamps have become common. Advantages of LEDs include no laser safety considerations, ease of home use, ability to irradiate a large area of tissue at once, possibility of wearable devices, and much lower cost per mW. LED photobiomodulation is here to stay.

Laser phototherapy induces angiogenesis in the periodontal tissue after delayed tooth replantation in rats

Background

Laser phototherapy (LPT) has been suggested as a new therapeutic tool to improve the repair of replanted teeth. However, its effects and mechanism of action are not yet completely understood.

Objectives

This study evaluated histologically the effect of laser phototherapy (LPT) λ808 and λ660 nm on angiogenesis in the periodontal tissue of replanted teeth in rats.

Material and Methods

Twenty maxillary right incisors were extracted from twenty Wistar rats and randomly assigned to four groups (n = 5): PN - teeth were stored in paper napkin for 45 min; WM - teeth were immersed in 20 ml of UHT whole cow milk for 45 min; PNL and WML - teeth received the same treatment described for PN and WM, respectively, plus LPT at λ808 and λ660 nm. All root canals were prepared and filled with calcium hydroxide paste. The animals were euthanized 15 days after tooth replantation and angiogenesis was scored by blood vessel counting in the area of periodontal ligament and alveolar bone, using the ImageJ software. Data were analyzed statistically by ANOVA and Tukey's test (α = 5%).

Results

LPT at λ808 and λ660 nm caused significant increased angiogenesis on irradiated groups (PNL and WML) when compared to the non-irradiated groups (PN and WM) (p<0.05). There was no statistically significant difference between PN and WM as well as between PNL and WML (p>0.05).

Conclusions

LPT is capable of stimulating angiogenesis in vivo in the periodontal tissue of replanted teeth. Key words:Angiogenesis, lasers, tooth avulsion, tooth replantation, wound healing.

LED phototherapy in full-thickness burns induced by CO2 laser in rats skin

Many studies have been conducted on the treatment of burns because they are important in morbidity and mortality. These studies are mainly focused on improving care and quality of life of patients. The aim of this study was evaluate the LED phototherapy effects in rats skin full-thickness burns induced by CO₂ laser. The animals were divided in NT group that did not received any treatment and LED group that received LED irradiation at 685 nm, 220 mW, and 4.5 J/cm² during 40 s by burned area. Biopsies were obtained after 7, 14, and 21 days of treatment and submitted to histological and immunohistochemical analysis. The LED phototherapy shows anti-inflammatory effects, improves angiogenesis, and stimulates the migration and proliferation of fibroblasts. The T CD8+ lymphocytes were more common in burned areas compared to T CD4+ lymphocytes since statistically significant differences were observed in the LED group compared to the NT group after 7 days of treatment. These results showed that LED phototherapy performs positive influence in full-thickness burns repair from the healing process modulated by cellular immune response. The obtained results allowed inferring that burns exhibit a characteristic cell immune response and this cannot be extrapolated to other wounds such as incision and wounds induced by punch, among others.

Only lasers can be used for low level laser therapy

The question of lasers' exclusivity, as well as the degree of influence of special properties of low-intensity laser illumination (LILI), such as coherence, polarity and monochromaticity, on the effectiveness of low level laser therapy (LLLT) continues to cause arguments. The study analyzes publications from 1973 to 2016, in which laser and conventional light sources are compared, and the following conclusions are drawn. First, there are a lot of publications with incorrect comparison or unfounded statements. Secondly, other sources of light are often meant by LILI without any justification. Thirdly, all studies, in which the comparison is carried out correctly and close parameters of the impact and the model are used, have a firm conclusion that laser light is much more effective. Fourthly, it is uniquely identified that the most important parameter that determines the efficiency of lasers is monochromaticity, i.e., a much narrower spectral width than for all other light sources. Only laser light sources can be used for LLLT!

Effects of light emitting diode irradiation on neural differentiation of human umbilical cord-derived mesenchymal cells

Recently, light emitting diodes (LEDs) have been introduced as a potential physical factor for proliferation and differentiation of various stem cells. Among the mesenchymal stem cells human umbilical cord matrix-derived mesenchymal (hUCM) cells are easily propagated in the laboratory and their low immunogenicity make them more appropriate for regenerative medicine procedures. We aimed at this study to evaluate the effect of red and green light emitted from LED on the neural lineage differentiation of hUCM cells in the presence or absence of retinoic acid (RA). Harvested hUCM cells exhibited mesenchymal and stemness properties. Irradiation of these cells by green and red LED with or without RA pre-treatment successfully differentiated them into neural lineage when the morphology of the induced cells, gene expression pattern (nestin, β-tubulin III and Olig2) and protein synthesis (anti-nestin, anti-β-tubulin III, anti-GFAP and anti-O4 antibodies) was evaluated. These data point for the first time to the fact that LED irradiation and optogenetic technology may be applied for neural differentiation and neuronal repair in regenerative medicine.

Adipose-derived stem cell spheroid treated with low-level light irradiation accelerates spontaneous angiogenesis in mouse model of hindlimb ischemia

BACKGROUND AIMS

We investigated whether low-level light irradiation (LLLI) before adipose-derived stromal cells (ASCs) spheroid transplantation improved hind-limb functional recovery by stimulation of angiogenesis.

METHODS

The spheroid, composed of ASCs, was irradiated with low-level light and expressed angiogenic factors, including vascular endothelial growth factor and basic fibroblast growth factor. From immunochemical staining analysis, the spheroid of ASCs included CD31⁺, KDR⁺ and CD34⁺, whereas monolayer-cultured ASCs were negative for these markers. To evaluate the therapeutic effect of the ASC spheroid treated with LLLI in vivo, phosphate-buffered saline, monolayer ASCs, LLLI-monolayer ASCs, spheroid ASCs and LLLI-spheroid ASCs were transplanted into a hind-limb ischemia model.

RESULTS

The LLLI-spheroid ASCs transplanted into the hind-limb ischemia differentiated into endothelial cells and remained differentiated. Transplantation of LLLI-spheroid ASCs into the hind-limb ischemia significantly elevated the density of vascular formations through angiogenic factors released by the ASCs and enhanced tissue regeneration at the lesion site. Consistent with these results, the transplantation of LLLI-spheroid ASCs significantly improved functional recovery compared with ASC or spheroid ASC transplantation and PBS treatment.

CONCLUSIONS

These findings suggest that transplantation of ASC spheroid treated with LLLI may be an effective stem cell therapy for the treatment of hind-limb ischemia and peripheral vascular disease.

Application of phototherapy for the healing of the navels of neonatal dairy calves

The present work evaluated the effects of LED light irradiation on the healing of the navels of neonatal dairy calves. Fifty-seven neonatal calves were divided into two groups. Animals had their umbilical stumps immersed in 10% iodine tincture for 60 s, and this process was repeated every 24 h for three consecutive days. The 29 animals in the first group did not receive LED therapy. The 28 animals in the second group received LED light irradiation at 640 nm with 300 mW power, 46.8 J/cm² energy density, 60 s irradiation time, and 0.385 cm² spot size. The animals were irradiated at four points (46.8 J/cm² per point) evenly distributed around the insertion site of the umbilical stump every 24 h for three consecutive days. Irradiation with LED light was applied before the umbilical stumps were immersed in the iodine solution. The time after birth at which the umbilical stump fell off of each calf was noted. The umbilical stumps of all animals fell off by the 25th day of age. After the umbilical stump fell off, the healing of the remnant wound was followed up to the 30th day after birth. The area of the wound was measured on the 15th, 20th, and 25th day after birth using digital photographs and computer-assisted area measurements. A two-tailed unpaired t test was applied to analyze the falling off the umbilical stump, whereas a Kruskal-Wallis one-way ANOVA test with a Dunn's multiple comparison test was used for the wound size evolution. GraphPad Prisma 5.0® and GraphPad StatMate 2.00® were used for the statistical analysis. The results revealed that phototherapy hastened the falling off the umbilical stump, accelerated navel healing, and reduced the mortality rate in newborn calves. Therefore, this study introduced a preventive and adjuvant after birth treatment that proved to be effective in reducing the incidences of omphalitis and newborn mortality.

5th Congress of WUWHS Abstract book Florence, Italy September 25–29 2016

The abstract book contains the abstracts of keynote lectures, focus sessions, symposia, workshops, AIUC annual meeting, AISLEC annual meeting, EPUAP annual meeting, ETRS special session, sponsor symposia, oral presentations, poster presentations and the subject index.

Photobiomodulation with LED and laser in repair of mandibular socket rabbit: clinical evaluation, histological, and histomorphometric

PURPOSE

The aim of this study was to evaluate the effects of LED and low-intensity laser on the healing of rabbit dental alveoli.

METHODS

A total of 18 rabbits were divided into three groups of six; all rabbits underwent surgical extraction of the first lower right premolar. Following surgery, group 1 received LED irradiation, group 2 received laser irradiation, and group 3 were untreated controls. The initial applications of LED and laser began 48 h after tooth extraction and were given perpendicularly to the dental alveoli. The three groups were clinically evaluated for 18 days in the postoperative period. At 90 days, the rabbits were euthanized and the mandibular fragments containing the healing alveoli were collected. These fragments initially underwent computed tomography scans and bone density was measured in Hounsfield units. Following this, the fragments were processed and stained with hematoxylin and eosin for histological and histomorphometric analysis.

RESULTS

The results were compatible between the clinical, histological, and histomorphometric parameters evaluated. There were no statistical differences between the LED and laser groups. However, the difference of the average bone density between laser and control group was not statistically significant.

CONCLUSIONS

It was found that photobiomodulation with LASER and LED presented effects. However, only the LED demonstrated a beneficial effect on the process of bone repair in the dental alveoli of rabbits.

Effect of low-level laser irradiation on proliferation of human dental mesenchymal stem cells; a systemic review

CONTEXT

Identification of factors that enhance the proliferation of human dental mesenchymal stem cells (DMSCs) is vital to facilitate tissue regeneration. The role of low-level laser irradiation (LLLI) on proliferation of human DMSCs has not been well established.

OBJECTIVE

To assess the effect of LLLI on proliferation of human DMSCs when applied in-vitro.

DATA SOURCES

Electronic search of literature was conducted (2000-2016) on PubMed, Web of Science, and Scopus databases. Search terms included low-level light therapy, low-level laser irradiation, low-level light irradiation, LLLT, humans, adolescent, adult, cells, cultured, periodontal ligament, dental pulp, stem cells, dental pulp stem cells, mesenchymal stem cells, periodontal ligament stem cell, deciduous teeth, cell proliferation, adult stem cells, radiation, and proliferation.

RESULTS

The literature search identified 165 studies with 6 being eligible for inclusion; all used diode lasers; 5 studies used InGaAIP diode lasers; 4 used 660nm, and the other two applied 810nm or 980nm wavelength LLLI. The distance between the DMSCs and the laser spot ranged between 0.5mm to 2mm. The time intervals of cell proliferation analysis ranged from 0h to 7days after LLLI. After 660nm LLLI, an increase in the DMSC's proliferation was reported [DMSCs extracted from dental pulp of deciduous teeth (two irradiations, 3J/cm(2), 20mW was more effective than 40mW), adult teeth (two irradiations, 0.5 and 1.0J/cm(2), 30mW), and from adult periodontal ligament (two irradiations, 1.0J/cm(2) was more effective than 0.5J/cm(2), 30mW)]. Similarly, an increase in the proliferation of DMSCs extracted from dental pulp of adult teeth was reported after 810nm LLLI (7 irradiations in 7days, 0.1 and 0.2J/cm(2), 60mW) or 980nm LLLI (single irradiation, 3J/cm(2), 100mW). However, 660nm LLLI in one study did not increase the proliferation of DMSCs (single irradiation, energy densities of 0.05, 0.30, 7, and 42J/cm(2), 28mW).

CONCLUSION

There is limited evidence that in-vitro LLLI (660/810/980nm, with energy densities of 0.1-3J/cm(2)) increases the proliferation of DMSCs. Considering the limited evidence and their method heterogeneity it is difficult to reach a firm conclusion. Further research is necessary to identify the optimal characteristics of the LLLI setting (wave length, energy density, power output, frequency/duration of irradiations, distance between the cells and the laser spot/probe) to increase proliferation of DMSCs, and assess its impact on replicative senescence, as well as determine feasibility of the use in the clinical setting.

Wound healing efficacy of a 660-nm diode laser in a rat incisional wound model

This study aimed to elucidate the optimum usage parameters of low reactive-level laser therapy (LLLT) in a rat incisional wound model. In Sprague-Dawley rats, surgical wounds of 15-mm length were made in the dorsal thoracic region. They were divided into groups to receive 660-nm diode laser irradiation 24 h after surgery at an energy density of 0 (control), 1, 5, or 10 J/cm². Tissue sections collected on postoperative day 3 were stained with hematoxylin-eosin and an antibody for ED1 to determine the number of macrophages around the wound. Samples collected on day 7 were stained with hematoxylin-eosin and observed via polarized light microscopy to measure the area occupied by collagen fibers around the wound; day 7 skin specimens were also subjected to mechanical testing to evaluate tensile strength. On postoperative day 3, the numbers of macrophages around the wound were significantly lower in the groups receiving 1 and 5 J/cm² irradiation, compared to the control and 10 J/cm² irradiation groups (p < 0.01). The area occupied by collagen fibers in day 7 was largest in 5 J/cm² group, followed by 1 J/cm² group, although this difference was not significant. The day 7 tensile test demonstrated significantly greater rupture strength in healing tissues from 1 and 5 J/cm² irradiation groups, compared to the control group (p < 0.05). Thus, LLLT with a 660-nm diode laser with energy density of 1 and 5 J/cm² enhanced wound healing in a rat incisional wound model. However, a higher radiation energy density yielded no significant enhancement.

Angiogenic Synergistic Effect of Adipose-Derived Stromal Cell Spheroids with Low-Level Light Therapy in a Model of Acute Skin Flap Ischemia

Human adipose-derived mesenchymal stem cells (hASCs) are an attractive cell source for tissue engineering. However, one obstacle to this approach is that the transplanted hASC population can decline rapidly in the recipient tissue. The aim of this study was to investigate the effects of low-level light therapy (LLLT) on transplanted spheroid hASCs in skin flaps of mice. hASCs were cultured in monolayers or spheroids. LLLT, hASCs, spheroids and spheroids transplanted with LLLT were applied to the skin flaps. Healing of the skin flaps was assessed by gross evaluation and by hematoxylin and eosin staining and elastin van Gieson staining. Compared with the spheroid group, skin flap healing was enhanced in the spheroid + LLLT group, including the neovascularization and regeneration of skin appendages. The survival of hASCs was enhanced by decreased apoptosis of hASCs in the skin flaps of the spheroid + LLLT group. The secretion of growth factors was stimulated in the spheroid + LLLT group compared with the ASC and spheroid groups. These data suggest that LLLT was an effective biostimulator of spheroid hASCs in the skin flaps, enhancing the survival of hASCs and stimulating the secretion of growth factors.

Low-level laser therapy/photobiomodulation in the management of side effects of chemoradiation therapy in head and neck cancer: part 2: proposed applications and treatment protocols

PURPOSE

There is a large body of evidence supporting the efficacy of low-level laser therapy (LLLT), more recently termed photobiomodulation (PBM) for the management of oral mucositis (OM) in patients undergoing radiotherapy for head and neck cancer (HNC). Recent advances in PBM technology, together with a better understanding of mechanisms involved and dosimetric parameters may lead to the management of a broader range of complications associated with HNC treatment. This could enhance patient adherence to cancer therapy, and improve quality of life and treatment outcomes. The mechanisms of action, dosimetric, and safety considerations for PBM have been reviewed in part 1. Part 2 discusses the head and neck treatment side effects for which PBM may prove to be effective. In addition, PBM parameters for each of these complications are suggested and future research directions are discussed.

METHODS

Narrative review and presentation of PBM parameters are based on current evidence and expert opinion.

RESULTS

PBM may have potential applications in the management of a broad range of side effects of (chemo)radiation therapy (CRT) in patients being treated for HNC. For OM management, optimal PBM parameters identified were as follows: wavelength, typically between 633 and 685 nm or 780-830 nm; energy density, laser or light-emitting diode (LED) output between 10 and 150 mW; dose, 2-3 J (J/cm(2)), and no more than 6 J/cm(2) on the tissue surface treated; treatment schedule, two to three times a week up to daily; emission type, pulsed (<100 Hz); and route of delivery, intraorally and/or transcutaneously. To facilitate further studies, we propose potentially effective PBM parameters for prophylactic and therapeutic use in supportive care for dermatitis, dysphagia, dry mouth, dysgeusia, trismus, necrosis, lymphedema, and voice/speech alterations.

CONCLUSION

PBM may have a role in supportive care for a broad range of complications associated with the treatment of HNC with CRT. The suggested PBM irradiation and dosimetric parameters, which are potentially effective for these complications, are intended to provide guidance for well-designed future studies. It is imperative that such studies include elucidating the effects of PBM on oncology treatment outcomes.

The Histopathological Investigation of Red and Blue Light Emitting Diode on Treating Skin Wounds in Japanese Big-Ear White Rabbit

The biological effects of different wavelengths of light emitting diode (LED) light tend to vary from each other. Research into use of photobiomodulation for treatment of skin wounds and the underlying mechanisms has been largely lacking. We explored the histopathological basis of the therapeutic effect of photobiomodulation and the relation between duration of exposure and photobiomodulation effect of different wavelengths of LED in a Japanese big-ear white rabbit skin-wound model. Skin wound model was established in 16 rabbits (three wounds per rabbit: one served as control, the other two wounds were irradiated by red and blue LED lights, respectively). Rabbits were then divided into 2 equal groups based on the duration of exposure to LED lights (15 and 30 min/exposure). The number of wounds that showed healing and the percentage of healed wound area were recorded. Histopathological examination and skin expression levels of fibroblast growth factor (FGF), epidermal growth factor (EGF), endothelial marker (CD31), proliferating cell nuclear antigen (Ki67) and macrophagocyte (CD68) infiltration, and the proliferation of skin collagen fibers was assessed. On days 16 and 17 of irradiation, the healing rates in red (15 min and 30 min) and blue (15 min and 30 min) groups were 50%, 37.5%, 25% and 37.5%, respectively, while the healing rate in the control group was 12.5%. The percentage healed area in the red light groups was significantly higher than those in other groups. Collagen fiber and skin thickness were significantly increased in both red light groups; expression of EGF, FGF, CD31 and Ki67 in the red light groups was significantly higher than those in other groups; the expression of FGF in red (30 min) group was not significantly different from that in the blue light and control groups. The effect of blue light on wound healing was poorer than that of red light. Red light appeared to hasten wound healing by promoting fibrous tissue, epidermal and endothelial cell proliferation. An increase in the exposure time to 30 min did not confer any additional benefit in both red and blue light groups. This study provides a theoretical basis for the potential therapeutic application of LED light in clinical settings.

Photobiomodulation in promoting wound healing: a review

Despite diverse methods being applied to induce wound healing, many wounds remain recalcitrant to all treatments. Photobiomodulation involves inducing wound healing by illuminating wounds with light emitting diodes or lasers. While used on different animal models, in vitro, and clinically, wound healing is induced by many different wavelengths and powers with no optimal set of parameters yet being identified. While data suggest that simultaneous multiple wavelength illumination is more efficacious than single wavelengths, the optimal single and multiple wavelengths must be better defined to induce more reliable and extensive healing of different wound types. This review focuses on studies in which specific wavelengths induce wound healing and on their mechanisms of action.

Activity of Porophyllum ruderale leaf extract and 670-nm InGaP laser during burns repair in rats

BACKGROUND

In this study, we investigated the effects of an extract of the leaves of Porophyllum ruderale and laser irradiation on the healing of burns.

METHODS

Seventy-two rats were divided in four groups: untreated controls, treated with laser irradiation, treated with P. ruderale and treated with both P. ruderale and laser irradiation. Burns were produced with a metal plate on the backs of the animals. Wound samples were collected for structural and morphometric analyses and to quantify the expression of TGF-β1 and VEGF.

RESULTS

Laser irradiation increased the number of fibroblasts, collagen fibers and newly formed vessels and decreased the number of granulocytes at the site of the wounds. Densitometric analysis revealed a significant increase in the expression of TGFβ-1 in the wounds treated with laser irradiation and with the P. ruderale extract at the beginning of the healing process and a decreased during the experimental period. The expression of VEGF was highlighted in the lesions irradiated with laser alone.

CONCLUSION

Inspite of not showing a beneficial effect on the laser combination with the P. ruderale extract, when the laser was used separately, a positive effects to enhance the healing of second-degree burns was promoted. P. ruderale was effective in decreasing the granulocytes during the repair process indicating a possible anti-inflammatory action of this extract of native flora, widely used in folk medicine, but little studied experimentally.

Enhancement of Ischemic Wound Healing by Spheroid Grafting of Human Adipose-Derived Stem Cells Treated with Low-Level Light Irradiation

We investigated whether low-level light irradiation prior to transplantation of adipose-derived stromal cell (ASC) spheroids in an animal skin wound model stimulated angiogenesis and tissue regeneration to improve functional recovery of skin tissue. The spheroid, composed of hASCs, was irradiated with low-level light and expressed angiogenic factors, including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), and hepatocyte growth factor (HGF). Immunochemical staining analysis revealed that the spheroid of the hASCs was CD31+, KDR+, and CD34+. On the other hand, monolayer-cultured hASCs were negative for these markers. PBS, human adipose tissue-derived stromal cells, and the ASC spheroid were transplanted into a wound bed in athymic mice to evaluate the therapeutic effects of the ASC spheroid in vivo. The ASC spheroid transplanted into the wound bed differentiated into endothelial cells and remained differentiated. The density of vascular formations increased as a result of the angiogenic factors released by the wound bed and enhanced tissue regeneration at the lesion site. These results indicate that the transplantation of the ASC spheroid significantly improved functional recovery relative to both ASC transplantation and PBS treatment. These findings suggest that transplantation of an ASC spheroid treated with low-level light may be an effective form of stem cell therapy for treatment of a wound bed.

The Use of Low Level Laser Therapy (LLLT) For Musculoskeletal Pain

Pain is the most common reason for physician consultation in the United States. One out of three Americans is affected by chronic pain annually. The number one reason for missed work or school days is musculoskeletal pain. Currently accepted therapies consist of non-steroidal anti-inflammatory drugs, steroid injections, opiate pain medications and surgery, each of which carries their own specific risk profiles. What is needed are effective treatments for pain which have an acceptably low risk-profile. For over forty years, low level laser (light) therapy (LLLT) and LED (light emitting diode) therapy (also known as photobiomodulation) has been shown to reduce inflammation and edema, induce analgesia, and promote healing in a range of musculoskeletal pathologies. The purpose of this paper is to review the use of LLLT for pain, the biochemical mechanisms of action, the dose response curves, and how LLLT may be employed by orthopedic surgeons to improve outcomes and reduce adverse events. With the predicted epidemic of chronic pain in developed countries, it is imperative to validate cost-effective and safe techniques for managing painful conditions which would allow people to live active and productive lives. Moreover the acceptance of LLLT (which is currently being used by many specialties around the world) into the armamentarium of the American health care provider would allow for additional treatment options for patients. A new cost-effective therapy for pain could elevate quality of life while reducing financial strains.