Effect of low-level light therapy on diabetic foot ulcers: a near-infrared spectroscopy study

Photobiomodulation using red and infrared spectrum light emitting-diode (LED) for the healing of diabetic foot ulcers: a controlled randomized clinical trial

Assessing the responses to the application of photobiomodulation using red and infrared spectrum light-emitting diodes (LED) on diabetic foot ulcers. Diabetic volunteers, of both genders, aged between 30 and 65 years, with grade I or II ulcers, were randomized into the groups: red LED, infrared LED, LED associated, and control. Home-based interventions took place on a daily basis for 12 weeks. Assessments of sample characterization were performed on day 1 and 90, and the variables wound healing index, mean skin temperature, sensitivity and pain in the wound area were measured at the pre-intervention time on days 1, 30, 60 and 90, with subsequent follow-up 30 days after the end of treatment. For statistical analysis, the software SPSS, version 17.0, intention-to-treat analysis, data normality was tested, and the linear mixed effects model, with a significance level of 5%. Magnitudes of clinical effect by Cohen's d. At the pre vs post intervention time of 90 days, we found a large clinical effect of G-LED V (d=1.7) and G -LED IV (d=1.6) in relation to G-C, where these intervention groups showed a tendency for faster wound healing compared to G-C. We also observed small clinical effect of G-LED IV, which showed greater reduction in the area in relation to G-LED V (d=0.4) and G-LED A (d=0.3). Conclusion: The use of individually applied red and infrared LED phototherapy clinically tended to be more effective for the reduction of diabetic foot ulcer areas, and infrared LED was the most effective. Trial registration: NCT03250533 (clinicaltrials.gov).

The Effects of Low-Level Laser Therapy on Wound Healing and Pain Management in Skin Wounds: A Systematic Review and Meta-Analysis

Low-level laser therapy (LLLT) is a non-invasive application of non-thermogenic light that is proven to promote tissue healing and alleviate pain. The authors aim to conduct the first meta-analysis, evaluating the effects of LLLT on wound healing and pain in skin wounds by comparing it to skin wounds not treated with LLLT. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed by searching the electronic databases. Eighteen randomised controlled trials that met the inclusion criteria were included in the study. Six hundred seventy skin wounds were analysed in the study. The primary outcome measures were the percentage reduction in wound size and the rate of complete wound healing. The secondary outcome measures included the visual analogue scale (VAS) for pain and the perineal pain score in episiotomy wounds. The percentage reduction of wound size in the LLLT group was significantly greater than that in the control group (95% confidence interval, CI, 13.93-37.70; p < 0.0001). In addition, the rate of wound healing was significantly greater in the LLLT group (95% CI, 2.32-16.70; p = 0.0003). LLLT has been shown to reduce pain, with the VAS scores for pain being significantly lower in the LLLT group after treatment (95% CI, -2.52 to -0.19; p = 0.02). The authors present the first meta-analysis within the literature showing the effects of LLLT on wound healing and pain in skin wounds. Higher quality trials are recommended to enhance the current evidence base.

Diabetic Foot Ulcer Imaging: An Overview and Future Directions

Diabetic foot ulcers (DFUs) affect one in every three people with diabetes. Imaging plays a vital role in objectively complementing the gold-standard visual yet subjective clinical assessments of DFUs during the wound treatment process. Herein, an overview of the various imaging techniques used to image DFUs is summarized. Conventional imaging modalities (e.g., computed tomography, magnetic resonance imaging, positron emission tomography, single-photon emitted computed tomography, and ultrasound) are used to diagnose infections, impact on the bones, foot deformities, and blood flow in patients with DFUs. Transcutaneous oximetry is a gold standard to assess perfusion in DFU cases with vascular issues. For a wound to heal, an adequate oxygen supply is needed to facilitate reparative processes. Several optical imaging modalities can assess tissue oxygenation changes in and around the wounds apart from perfusion measurements. These include hyperspectral imaging, multispectral imaging, diffuse reflectance spectroscopy, near-infrared (NIR) spectroscopy, laser Doppler flowmetry or imaging, and spatial frequency domain imaging. While perfusion measurements are dynamically monitored at point locations, tissue oxygenation measurements are static two-dimensional spatial maps. Recently, we developed a spatio-temporal NIR-based tissue oxygenation imaging approach to map for the extent of asynchrony in the oxygenation flow patterns in and around DFUs. Researchers also measure other parameters such as thermal maps, bacterial infections (from fluorescence maps), pH, collagen, and trans-epidermal water loss to assess DFUs. A future direction for DFU imaging would ideally be a low-cost, portable, multi-modal imaging platform that can provide a visual and physiological assessment of wounds for comprehensive wound care intervention and management.

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.

Diabetic foot ulcer: Challenges and future

Diabetic foot ulcers (DFUs) have become one of the important causes of mortality and morbidity in patients with diabetes, and they are also a common cause of hospitalization, which places a heavy burden on patients and society. The prevention and treatment of DFUs requires multidisciplinary management. By controlling various risk factors, such as blood glucose levels, blood pressure, lipid levels and smoking cessation, local management of DFUs should be strengthened, such as debridement, dressing, revascularization, stem cell decompression and oxygen therapy. If necessary, systemic anti-infection treatment should be administered. We reviewed the progress in the clinical practice of treating DFUs in recent years, such as revascularization, wound repair, offloading, stem cell transplantation, and anti-infection treatment. We also summarized and prospectively analyzed some new technologies and measurements used in the treatment of DFUs and noted the future challenges and directions for the development of DFU treatments.

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.

Near infrared spectroscopy in peripheral artery disease and the diabetic foot: A systematic review

With the need for tools that assess microvascular status in diabetic foot disease (DFD) being clear, near infrared spectroscopy (NIRS) is a putative method for noninvasive testing of the diabetic foot. The use of NIRS in patients with peripheral arterial disease (PAD) has extended to its role in studying the pathophysiology of DFD. NIRS generates metrics such as recovery time, deoxygenation, oxygen consumption (VO₂ ), tissue oxygen saturation (StO₂ ), total haemoglobin (HbT), and oxyhaemoglobin area under the curve (O₂ Hb_AUC ). NIRS may potentially help the multidisciplinary team stratify limbs as high-risk, especially in diabetic patients with symptoms masked by peripheral neuropathy. NIRS may be useful for assessing treatment effectiveness and preventing deterioration of patients with PAD.

Evolving spectrum of diabetic wound: Mechanistic insights and therapeutic targets

Diabetes mellitus is a chronic metabolic disorder resulting in an increased blood glucose level and prolonged hyperglycemia, causes long term health conse-quences. Chronic wound is frequently occurring in diabetes patients due to compromised wound healing capability. Management of wounds in diabetic patients remains a clinical challenge despite many advancements in the field of science and technology. Increasing evidence indicates that alteration of the biochemical milieu resulting from alteration in inflammatory cytokines and matrix metalloproteinase, decrease in fibroblast and keratinocyte functioning, neuropathy, altered leukocyte functioning, infection, etc., plays a significant role in impaired wound healing in diabetic people. Apart from the current pharmacotherapy, different other approaches like the use of conventional drugs, antidiabetic medication, antibiotics, debridement, offloading, platelet-rich plasma, growth factor, oxygen therapy, negative pressure wound therapy, low-level laser, extracorporeal shock wave bioengineered substitute can be considered in the management of diabetic wounds. Drugs/therapeutic strategy that induce angiogenesis and collagen synthesis, inhibition of MMPs, reduction of oxidative stress, controlling hyperglycemia, increase growth factors, regulate inflammatory cytokines, cause NO induction, induce fibroblast and keratinocyte proliferation, control microbial infections are considered important in controlling diabetic wound. Further, medicinal plants and/or phytoconstituents also offer a viable alternative in the treatment of diabetic wound. The focus of the present review is to highlight the molecular and cellular mechanisms, and discuss the drug targets and treatment strategies involved in the diabetic wound.

Photobiomodulation Response From 660 nm is Different and More Durable Than That From 980 nm

BACKGROUND AND OBJECTIVES

Photobiomodulation (PBM) therapy uses light at various wavelengths to stimulate wound healing, grow hair, relieve pain, and more-but there is no consensus about optimal wavelengths or dosimetry. PBM therapy works through putative, wavelength-dependent mechanisms including direct stimulation of mitochondrial respiration, and/or activation of transmembrane signaling channels by changes in water activity. A common wavelength used in the visible red spectrum is ~660 nm, whereas recently ~980 nm is being explored and both have been proposed to work via different mechanisms. We aimed to gain more insight into identifying treatment parameters and the putative mechanisms involved.

STUDY DESIGN/MATERIALS AND METHODS

Fluence-response curves were measured in cultured keratinocytes and fibroblasts exposed to 660 or 980 nm from LED sources. Metabolic activity was assessed using the MTT assay for reductases. ATP production, a major event triggered by PBM therapy, was assessed using a luminescence assay. To measure the role of mitochondria, we used an ELISA to measure COX-1 and SDH-A protein levels. The respective contributions of cytochrome c oxidase and ATP synthase to the PBM effects were gauged using specific inhibitors.

RESULTS

Keratinocytes and fibroblasts responded differently to exposures at 660 nm (red) and 980 nm (NIR). Although 980 nm required much lower fluence for cell stimulation, the resulting increase in ATP levels was short-term, whereas 660 nm stimulation elevated ATP levels for at least 24 hours. COX-1 protein levels were increased following 660 nm treatment but were unaffected by 980 nm. In fibroblasts, SDH-A levels were affected by both wavelengths, whereas in keratinocytes only 660 nm light impacted SDH-A levels. Inhibition of ATP synthase nearly completely abolished the effects of both wavelengths on ATP synthesis. Interestingly, inhibiting cytochrome c oxidase did not prevent the rise in ATP levels in response to PBM treatment.

CONCLUSION

To the best of our knowledge, this is the first demonstration of differing kinetics in response to PBM therapy at red versus NIR wavelength. We also found cell-type-specific differences in PBM therapy response to the two wavelengths studied. These findings confirm that different response pathways are involved after 660 and 980 nm exposures and suggest that 660 nm causes a more durable response. © 2021 Wiley Periodicals LLC.

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.

Photobiomodulation therapy improves the growth factor and cytokine secretory profile in human type 2 diabetic fibroblasts

Impaired wound healing is a common complication of diabetes mellitus (DM) and the underlying mechanism of this impairment is still unclear. Fibroblast, as the main reconstructing cell, secretes some critical growth factors and cytokine contributing to wound healing. It is well known that DM alters the behavior of these cells and photobiomodulation therapy (PBMT) compensates some impairments in diabetic fibroblasts. Therefore, the aim of the present study was to demonstrate the impact of diabetes and the role of PBMT through low level laser irradiation on secretory profile of human diabetic fibroblasts. Primary human dermal fibroblasts from normal (HDFs) and diabetic (DHDFs) donors were harvested. For PBMT, the DHDFs were irradiated with a Helium-Neon laser at 632.8 nm wavelength and energy density of 0.5 J/cm², as laser treated group (LT-DHDFs). Next, some cellular behaviors and secretory profiling array for 60 growth factors/cytokines were investigated in LT-DHDFs and then compared with those of controls. The data showed that the PBMT could compensate such impairments occurred in DHDFs in terms of viability, proliferation, and migration. Furthermore, considering our novel findings, out of those 20 growth factors/cytokines involved in cell proliferation, immune system regulation, and cell-cell communication pathways, which significantly decreased in DHDF as compared with HDFs, the PBMT could compensate seven in LT-DHDFs as compared with DHDFs. The seven growth factor/cytokines, which are mainly involved in cell-cell communication, positive regulation of cell proliferation, and chemokine mediated pathway included BDNF, Eotaxin-3, FGF6, FGF7, Fractalkine, fit-3ligand, and GCP-2. Therefore, it is suggested that scrutinizing these differentially secreted molecules and the impaired pathways in DHDFs, in combination with those compensated in LT-DHDFs, could raise our knowledge to manage diabetic ulcer through a feasible and cost effective intervention, specifically PBMT.

Efeitos da laserterapia de baixa intensidade na cicatrização de úlceras nos pés em pessoas com diabetes mellitus

Objetivo: Identificar os efeitos da laserterapia de baixa intensidade na cicatrização do pé diabético. Método: Revisão sistemática nas bases de dados PubMed, LILACS, SciELO, CINAHL, Cochrane, Web of Science e Scopus, em que foram identificados 73 artigos, dos quais seis foram incluídos na amostra final, após verificação dos critérios de elegibilidade. Resultados: Os artigos apontaram como efeitos da laserterapia a efetividade na progressão do processo de reparo tecidual do pé diabético, alívio da dor, ação antiinflamatória, aumento da perfusão tecidual da lesão e melhora da resposta vascular e do sistema nervoso. Conclusão: O laser é uma terapia adjuvante que pode acelerar o processo de cicatrização da lesão, diminuir a dor, melhorar a neovascularização e, assim, minimizar o risco de complicações, como amputação do membro inferior e melhora da qualidade de vida de pessoas com diabetes e integridade da pele prejudicada.

Effects of low-level laser therapy on the healing of foot ulcers in people with diabetes mellitus

Objective: Identify the effects of low-level laser therapy on the healing of diabetic foot. Method: Systematic review of the PubMed, LILACS, SciELO, CINAHL, Cochrane, Web of Science and Scopus databases, in which 92 articles were identified and six were included in the final sample after the eligibility criteria. Results: The articles pointed out as effects of laser therapy the effectiveness in the progression of the tissue repair process of the diabetic foot, pain relief, anti-inflammatory action, increased tissue perfusion of the lesion and improvement of the vascular response and the nervous system. Conclusion: Laser is an adjuvant therapy that can accelerate the wound healing process, relieve pain, improve neovascularization, and thus minimize the risk of complications, such as lower limb amputation and improvement of quality of life for people with diabetes and impaired skin integrity.

Efficacy of low-level light therapy for treatment of diabetic foot ulcer: A systematic review and meta-analysis of randomized controlled trials

AIMS

The goal of this systematic review and meta-analysis based on seven Randomized control trials (RCTs) is to examine whether Low-level light therapy (LLLT) is effective at healing diabetic foot ulcer (DFU) and to provide evidence-based recommendations and clinical guidelines for the future clinical treatment of DFUs.

METHODS

Medline, Embase, Scopus, Cochrane Library, and Web of Science databases were searched for studies published up to June 30, 2017, without language or data restrictions. RCTs that investigated the use of LLLT for DFU treatment were included. Standard methods of meta-analysis were performed to evaluate outcomes of LLLT on the healing of DFU.

RESULTS

Seven RCTs involving 194 participants were eligible for this systematic review and meta-analysis. The results of meta-analysis showed that LLLT has emerged as a potential noninvasive treatment for DFUs, as LLLT was found to effectively reduce the ulcer area [weighted mean difference (WMD) 34.18, 95% confidence intervals (CI) 19.38-48.99, P < 0.00001], improve the complete healing rate [odds ratio (OR) 6.72, 95% CI 1.99-22.64, P = 0.002]. Qualitative analysis of the included RCTs found that LLLT also played a role in the treatment of DFUs through promoting rapid granulation formation and shortening ulcer closure time, as well as alleviating foot ulcer pain. None of the treatment-related adverse event was reported.

CONCLUSIONS

LLLT was recognized as a potential method in the comprehensive treatment of DFUs. Further well designed and high-quality studies are required to confirm the role of LLLT in the management of DFUs.

Low-level laser therapy for treatment of venous ulcers evaluated with the Nursing Outcome Classification: study protocol for a randomized controlled trial

BACKGROUND

Different methods are available for the treatment of venous ulcers. Most current approaches focus on a combination of topical and compressive therapy. Adjuvant low-level laser therapy may be helpful in lesions with a protracted healing course, but evidence for its use is still limited. This paper describes the protocol of a randomized controlled trial designed to compare the effect of adjuvant low-level laser therapy versus conventional venous ulcer tissue repair, evaluated by a nurse using clinical indicators from the Nursing Outcomes Classification (NOC).

METHODS/DESIGN

For this prospective randomized controlled trial, 40 adult patients of both sexes with active venous ulcers will be recruited. Subjects will be selected by the sealed-envelope method without any annotation or external identification that might refer to the type of study group. At the time of unblinding, a label with the description of the group to which the patient belongs (that is, control or intervention) will be found inside the envelope. Conventional treatment (topical medication and compressive therapy) will be offered to both groups. Additionally, the intervention group will receive adjuvant low-level laser therapy. All patients will be followed weekly until ulcer healing or for a maximum of 16 weeks. Evaluation of tissue repair will be based on 14 clinical indicators drawn from NOC for wound healing (secondary intention) and tissue integrity (skin and mucous membranes). The primary endpoint will be decreased wound size and scar formation. This laser therapy is expected to enhance the quality, speed, and effectiveness of the treatment of venous ulcers, a chronic condition. This should reduce associated costs to the health service and allow patients to resume their daily activities sooner.

DISCUSSION

This randomized clinical trial will use a validated method to investigate the effect of a novel intervention for the treatment of venous ulcers.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03229330 . Registered on July 2017.