Shedding light on a new treatment for diabetic wound healing: a review on phototherapy

A Comprehensive Systematic Review of the Effects of Photobiomodulation Therapy in Different Light Wavelength Ranges (Blue, Green, Red, and Near-Infrared) on Sperm Cell Characteristics in Vitro and in Vivo

Around 7% of the male population in the world are entangle with considerable situation which is known as male infertility. Photobiomodulation therapy (PBMT) is the application of low-level laser radiation, that recently used to increase or promote the various cell functions including, proliferation, differentiation, ATP production, gene expressions, regulation of reactive oxygen spices (ROS), and also boost the tissue healing and reduction of inflammation. This systematic review's main idea is a comprehensive appraisal of the literatures on subjects of PBMT consequences in four light ranges wavelength (blue, green, red, near-infrared (NIR)) on sperm cell characteristics, in vitro and in vivo. In this study, PubMed, Google Scholar, and Scopus databases were used for abstracts and full-text scientific papers published from 2003-2023 that reported the application of PBM on sperm cells. Criteria's for inclusion and exclusion to review were applied. Finally, the studies that matched with our goals were included, classified, and reported in detail. Also, searched studies were subdivided into the effects of four ranges of light irradiation, including the blue light range (400-500 nm), green light range (500-600 nm), red light range (600-780 nm), and NIR light range (780-3000 nm) of laser irradiation on human or animal sperm cells, in situations of in vitro or in vivo. Searches with our keywords results in 137 papers. After primary analysis, some articles were excluded because they were review articles or incomplete and unrelated studies. Finally, we use the 63 articles for this systematic review. Our category tables were based on the light range of irradiation, source of sperm cells (human or animal cells) and being in vitro or in vivo. Six% of publications reported the effects of blue, 10% green, 53% red and 31% NIR, light on sperm cell. In general, most of these studies showed that PBMT exerted a positive effect on the sperm cell motility. The various effects of PBMT in different wavelength ranges, as mentioned in this review, provide more insights for its potential applications in improving sperm characteristics. PBMT as a treatment method has significant effectiveness for treatment of different medical problems. Due to the lack of reporting data in this field, there is a need for future studies to assessment the biochemical and molecular effects of PBMT on sperm cells for the possible application of this treatment to the human sperm cells before the ART process.

IL-1β Antagonist Receptor Peptide Associated with Photobiomodulation Accelerates Diabetic Wound Tissue Repair

Chronic hyperglycemia caused by diabetes mellitus (DM) slows down the healing process due to prolonged inflammation which impedes the regeneration progression. Photobiomodulation (PBM) is considered a non-pharmacological intervention and has anti-inflammatory and biostimulatory effects that accelerate the healing process. Currently found IL-1β inhibitors are difficult to implement due to their cytotoxic potential, excessive amounts, and invasive administration, and therefore, the application of this peptide in diabetic wounds represents a promising intervention to help resolve the inflammatory response. This study aimed to investigate the effect of an IL-1β inhibitor molecule associated with PBM irradiation in a model of epithelial injury in diabetic mice. After the induction of the DM model with streptozotocin (STZ), the skin lesion model was implemented through surgical excision. Sixty C57BL/6 mice divided into five experimental groups (n = 12) were used: excisional wound (EW), DM + EW, DM + EW + DAP 1-2 (inhibitor peptide), DM + EW + PBM, and DM + EW + PBM + DAP 1-2. Treatment started 12 h after wound induction and was performed daily for 5 days. Twenty-four hours after the last application, the animals were euthanized and the outer edge of the wound was removed. The results obtained demonstrate that the DM + EW + PBM + DAP 1-2 group caused a reduction in the levels of pro-inflammatory cytokines, an increase in anti-inflammatory cytokines, and an increase in TGF-β and maintenance of the cellular redox state with a consequent reduction in levels of inflammatory infiltrate and concomitant stimulation of type III collagen gene expression, as well as a decrease in the size of the wound in square centimeter 6 days after the injury. Only the combination of therapies was able to favor the process of tissue regeneration due to the development of an approach capable of acting at different stages of the regenerative process, through the mechanisms of action of interventions on the inflammatory process by avoiding its stagnation and stimulating progression of regeneration.

Branched fructo-oligosaccharides from Polygonatum Cyrtonema Hua as crosslinking agents for cellulose: A novel injectable and on-demand dissolution hydrogel for diabetic wound

Oligosaccharide-containing macromolecular bio adhesives are emerging as highly promising eco-friendly materials to enhance the cytocompatibility of viscous hydrogels for wound healing applications. In our prior research, we extensively elucidated the properties of branch-structure fructo-oligosaccharides derived from Polygonatum Cyrtonema Hua (referred to as PCOS). However, the characteristics of hydrogels based on fructo-oligosaccharides remain to be fully explored. In present work, we developed an injectable, PCOS/carboxymethyl cellulose (CMC) hydrogel which is a dual ion-physical cross-linked hydrogel that can be considered as a potential diabetic wound dressing. The tests showed that the optimal ratios for hydrogel preparation were 2 % CBM 940 (Carbomer 940), 5 % CMC and 10 % PCOS. The resultant hydrogel was formulated into composite hydrogels that were then used for the treatment of full-thickness excisional wounds in a db/db diabetic mouse model. Wound closure and histological evaluation confirmed its beneficial effect on wound healing. Further morphological analysis through scanning electron microscopy images revealed a porous hydrogel structure, while Fourier-transform infrared spectroscopy provided structural insights on the crosslinking reaction. Physicochemical properties of the hybrid hydrogels determined by rheological properties, thermogravimetric, water loss rate, et al., indicated that the double crosslinking PCOS/CMC hybrid hydrogel showed enhanced dynamic mechanical properties and water retention capacity compared to the CMC cellulose matrix hydrogels. Thus, this novel PCOS-hybrid hydrogel exhibited good dissolvability and injectable properties, which was proved to facilitate for the diabetic wound healing both in vitro and in vivo test and holds a potential clinical application in the wound healing.

Dose-response relationship of photobiomodulation therapy and oxidative stress markers in healing dynamics of diabetic neuropathic ulcers in Wistar rats

Purpose

Diabetic foot ulcers are reported to be the most expensive complications of diabetes, with high morbidity and mortality rates. If the necessary care is not provided for the wound to heal, the individual may end up amputating the affected feet. Photobiomodulation therapy is a promising non-pharmacological treatment option for wound healing. The objective of the present study is to establish a dose-response relationship between photobiomodulation therapy and oxidative stress markers in the healing dynamics of diabetic neuropathic ulcers in Wistar rats.

Methodology

Diabetic neuropathy was induced in 126 Albino Wistar rats. An excisional wound of an area of 2cm2 was made on the neuropathy-induced leg. Photobiomodulation therapy of dosages 4, 6, 8, 10, 12, and 15 J/cm2 of wavelengths 655 and 808 nm was irradiated. The control group animals were kept un-irradiated. The outcome measures were assessed during wound healing's inflammatory, proliferative and remodelling phases.

Results

In the experimental group, animals treated with photobiomodulation therapy at doses of 4, 6, and 8 J/cm2 showed better wound healing dynamics. Photobiomodulation therapy modulated the reactive oxygen species and antioxidant levels, thereby improving the oxidative status of the wound.

Conclusion

Photobiomodulation therapy of dosages 4, 6, and 8 J/cm2 is effective and is a promising adjuvant modality in treating diabetic neuropathic ulcers. There was a strong dose-response relationship in the experimental groups treated with 4, 6 and 8 J/ cm2.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-022-01157-2.

Photobiomodulation at 660 nm Stimulates In Vitro Diabetic Wound Healing via the Ras/MAPK Pathway

Diabetic foot ulcers (DFUs) are open chronic wounds that affect diabetic patients due to hyperglycaemia. DFUs are known for their poor response to treatment and frequently require amputation, which may result in premature death. The present study evaluated the effect of photobiomodulation (PBM) at 660 nm on wound healing via activation of Ras/MAPK signalling in diabetic wounded cells in vitro. This study used four human skin fibroblast cell (WS1) models, namely normal (N), wounded (W), diabetic (D), and diabetic wounded (DW). Cells were irradiated at 660 nm with 5 J/cm2. Non-irradiated cells (0 J/cm2) served as controls. Cells were incubated for 24 and 48 h post-irradiation, and the effect of PBM on cellular morphology and migration rate, viability, and proliferation was assessed. Basic fibroblast growth factor (bFGF), its phosphorylated (activated) receptor FGFR, and phosphorylated target proteins (Ras, MEK1/2 and MAPK) were determined by enzyme-linked immunosorbent assay (ELISA) and Western blotting; nuclear translocation of p-MAPK was determined by immunofluorescence. PBM resulted in an increase in bFGF and a subsequent increase in FGFR activation. There was also an increase in downstream proteins, p-Ras, p-MEK1/2 and p-MAPK. PBM at 660 nm led to increased viability, proliferation, and migration as a result of increased bFGF and subsequent activation of the Ras/MAPK signalling pathway. Therefore, this study can conclude that PBM at 660 nm stimulates in vitro diabetic wound healing via the bFGF-activated Ras/MAPK pathway.

Injectable self-healing chitosan-based POSS-PEG hybrid hydrogel as wound dressing to promote diabetic wound healing

Promoting the healing of diabetic wounds remains a major challenge in scientific research today. A star-like eight-arm cross-linker octafunctionalized POSS of benzaldehyde-terminated polyethylene glycol (POSS-PEG-CHO) was synthesized, and crosslinked with hydroxypropyltrimethyl ammonium chloride chitosan (HACC) via Schiff base reaction to obtain Chitosan-based POSS-PEG hybrid hydrogels. The designed composite hydrogels exhibited strong mechanical strength, injectability, excellent self-healing efficiency, good cytocompatibility and antibacterial properties. Furthermore, the composite hydrogels could accelerate cells migration and proliferation, as expected by remarkably promoting wound healing in diabetic mice. The wounds treated with the composite hydrogels displayed faster regeneration of epithelial tissue, fewer inflammatory cells, more collagen deposition and higher expression level of VEGF. Therefore, Chitosan-based POSS-PEG hybrid hydrogel has great application potential as a dressing for promoting the healing of diabetic wounds.

Dose-Response Relationship of Photobiomodulation Therapy on Matrix Metalloproteinase in Healing Dynamics of Diabetic Neuropathic Ulcers-An in vivo Study

Individuals with diabetic foot ulcers have overlapped the inflammatory, proliferative and remodeling phase, making the tissue vulnerable to delayed healing responses. We aimed to establish the dose-response relationship of photobiomodulation therapy of different doses and matrix metalloproteinases in the healing dynamics of diabetic neuropathic ulcers. Diabetes was induced in 126 Albino Wistar rats, and neuropathy was induced to the hind paw by a sciatic nerve injury method. An excisional wound was created on the neuropathy-induced leg. Photobiomodulation therapy of dosages 4, 6, 8, 10, 12 and 15 J cm^-2 and wavelength 655 nm and 808 nm was irradiated. Photobiomodulation therapy of dosages 4, 6 and 8 J cm^-2 showed better wound healing properties with optimized levels of matrix metalloproteinases-1 and 8. We observed a strong dose response in the experimental group treated with 6 and 8 J cm^-2 . The findings from the present study conclude that photobiomodulation therapy of dosages 4, 6 and 8 J cm^-2 is suggestive of usefulness in diabetic neuropathic ulcer healing. Markers like matrix metalloproteinases may give a clear direction on response to the therapy. Based on the findings from the present study, we recommend to validate the findings for safety and efficacy in future through human prospective randomized controlled clinical trials.

The Effects of Blue Light on Human Fibroblasts and Diabetic Wound Healing

Diabetes is a serious threat to global health and is among the top 10 causes of death. The Diabetic foot ulcer (DFU) is among the most common and severe complications of the disease. Bacterial infections are common; therefore, timely aggressive management, using multidisciplinary management approaches is needed to prevent complications, morbidity, and mortality, particularly in view of the growing cases of antibiotic-resistant bacteria. Photobiomodulation (PBM) involves the application of low-level light at specific wavelengths to induce cellular photochemical and photophysical responses. Red and near-infrared (NIR) wavelengths have been shown to be beneficial, and recent studies indicate that other wavelengths within the visible spectrum could be helpful as well, including blue light (400–500 nm). Reports of the antimicrobial activity and susceptibility of blue light on several strains of the same bacterium show that many bacteria are less likely to develop resistance to blue light treatment, meaning it is a viable alternative to antibiotic therapy. However, not all studies have shown positive results for wound healing and fibroblast proliferation. This paper presents a critical review of the literature concerning the use of PBM, with a focus on blue light, for tissue healing and diabetic ulcer care, identifies the pros and cons of PBM intervention, and recommends the potential role of PBM for diabetic ulcer care.

Amitriptyline-Based Biodegradable PEG-PLGA Self-Assembled Nanoparticles Accelerate Cutaneous Wound Healing in Diabetic Rats

The aim of this work was to study the healing activity of amitriptyline (Amitrip) in rat diabetic wounds. A nanoformula of the drug was prepared as Amitrip-based biodegradable PEG-PLGA self-assembled nanoparticles (Amitrip-NPs) with a mean particle size of 67.4 nm. An in vivo investigation was conducted to evaluate the wound-healing process of Amitrip-NPs in streptozotocin-induced diabetic rats. Wound contraction was accelerated in rats treated with Amitrip-NPs. Histological examinations confirmed these findings, with expedited remodeling and collagen deposition in the NPs-treated animals. The formula showed anti-inflammatory activities as demonstrated by inhibition of interleukin-6 (IL-6) expression and tumor necrosis factor-α (TNF-α) expression, as well as enhanced expression of interleukin-10 (IL-10). In addition, Amitrip-NPs protected against malondialdehyde (MDA) buildup and superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymatic exhaustion. The pro-collagen activity of Amitrip-NPs was confirmed by the observed enhancement of hydroxyproline wounded skin content, upregulation of Col 1A1 mRNA expression and immune expression of collagen type IV expression. Further, Amitrip-NPs significantly increased expression transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor-A (VEGF-A), platelet-derived growth factor-B (PDGF-B) and cluster of differentiation 31 (CD31). In conclusion, the developed Amitrip-NPs expedited wound healing in diabetic rats. This involves anti-inflammatory, antioxidant, pro-collagen and angiogenic activities of the prepared NPs. This opens the gate for evaluating the usefulness of other structurally related tricyclic antidepressants in diabetic wounds.

The EPICC Family of Anti-Inflammatory Peptides: Next Generation Peptides, Additional Mechanisms of Action, and In Vivo and Ex Vivo Efficacy

The EPICC peptides are a family of peptides that have been developed from the sequence of the capsid protein of human astrovirus type 1 and previously shown to inhibit the classical and lectin pathways of complement. The EPICC peptides have been further optimized to increase aqueous solubility and identify additional mechanisms of action. Our laboratory has developed the lead EPICC molecule, PA-dPEG24 (also known as RLS-0071), which is composed of a 15 amino acid peptide with a C-terminal monodisperse 24-mer PEGylated moiety. RLS-0071 has been demonstrated to possess other mechanisms of action in addition to complement blockade that include the inhibition of neutrophil-driven myeloperoxidase (MPO) activity, inhibition of neutrophil extracellular trap (NET) formation as well as intrinsic antioxidant activity mediated by vicinal cysteine residues contained within the peptide sequence. RLS-0071 has been tested in various ex vivo and in vivo systems and has shown promise for the treatment of both immune-mediated hematological diseases where alterations in the classical complement pathway plays an important pathogenic role as well as in models of tissue-based diseases such as acute lung injury and hypoxic ischemic encephalopathy driven by both complement and neutrophil-mediated pathways (i.e., MPO activity and NET formation). Next generation EPICC peptides containing a sarcosine residue substitution in various positions within the peptide sequence possess aqueous solubility in the absence of PEGylation and demonstrate enhanced complement and neutrophil inhibitory activity compared to RLS-0071. This review details the development of the EPICC peptides, elucidation of their dual-acting complement and neutrophil inhibitory activities and efficacy in ex vivo systems using human clinical specimens and in vivo efficacy in animal disease models.

Photobiomodulation at 830 nm Stimulates Migration, Survival and Proliferation of Fibroblast Cells

PURPOSE

Photobiomodulation (PBM) promotes diabetic wound healing by favoring cell survival and proliferation. This study aimed to investigate the potential of PBM in stimulating cellular migration, viability, and proliferation using the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway.

METHODS

The study explored the in vitro effects of near infrared (NIR) light on cell viability (survival) and proliferation as well as the presence of TGF-β1, phosphorylated TGF-β receptor type I (pTGF-βR1) and phosphorylated mothers against decapentaplegic-homolog (Smad)-2/3 (p-Smad2/3) in different fibroblast cell models.

RESULTS

Results show a significant increase in cellular migration in wounded models, and increased viability and proliferation in irradiated cells compared to their respective controls. An increase in the presence of TGF-β1 in the culture media, a reduction in pTGF-βR1 and a slight presence of p-Smad2/3 was observed in the cells.

CONCLUSION

These findings show that PBM at 830 nm using a fluence of 5 J/cm² could induce cell viability, migration and proliferation to favor successful healing of diabetic wounds. This study contributes to the growing body of knowledge on the molecular and cellular effect of PBM and showcases the suitability of PBM at 830 nm in managing diabetic wounds.

Synergistic Effects of Photobiomodulation Therapy with Combined Wavelength on Diabetic Wound Healing In Vitro and In Vivo

Objective: The difficulty in chronic diabetic wound healing remains the focus of clinical research. Photobiomodulation therapy (PBMT) with different wavelengths could exert different effects on wound healing, but the effects of combined red and blue light (BL) remained unclear. Methods: Diabetic rat wound model and diabetic wounded endothelial cell model were established to observe possible effects of PBMT using combined wavelengths for wound healing. Cells and animals were separated into four groups exposed to red and/or BL. Cell viability, apoptosis, and migration, as well as the expression level of nitric oxide (NO), vascular endothelial growth factor, interleukin-6, and tumor necrosis factor-α were measured in vitro. Diabetic rats were evaluated for wound closure rates, collagen deposition, inflammation intensity, and density of neovascularization after light irradiation. Results: PBMT using combined wavelengths significantly sped up the healing process with increasing angiogenesis density, collagen deposition, and alleviating inflammation in vivo. Moreover, combined wavelength irradiation promoted cell proliferation and migration, and NO production, as well as reduced reactive oxygen species and inflammation in vitro. Conclusions: PBMT using combined wavelengths performed a synergistic effect for promoting diabetic wound healing and would be helpful to explore a more efficient pattern toward chronic wound healing.

Extracellular Vesicles from HIF-1α-Overexpressing Adipose-Derived Stem Cells Restore Diabetic Wounds Through Accelerated Fibroblast Proliferation and Migration

PURPOSE

Inhibition of cellular adaptation to hypoxia can cause persistent inflammation, thereby increasing tissue damage and complicating wound healing in diabetes patients. Regulating cellular adaptation to hypoxic environments can help in effective wound repair. Hypoxia-inducible factor (HIF)-1α is a key regulator of cell hypoxia. Extracellular vesicles (EVs) regulate wound repair. This study investigated the mechanism of HIF-1α overexpression in adipose-derived stem cell extracellular vesicles (ADSCs-hEVs) in the repair of diabetic wounds.

MATERIALS AND METHODS

HIF-1α expression in diabetes patients and healthy participants was studied. High-throughput sequencing, GO, and KEGG analysis revealed that ADSCs small extracellular vesicle hypoxia environments may increase HIF-1α expression by affecting cell metabolism, differentiation, and TGF-β secretion, or by altering the PI3K/AKT pathway. Effect of addition of ADSCs-hEVs on cell proliferation and migration was investigated using Western blotting, EdU assay, transwell assay, and migration. In vivo, after 7, 14, and 21 days, important factors for diabetic wound healing were evaluated by immunohistochemistry, qRT-PCR, Masson staining, and H&E staining.

RESULTS

HIF-1α expression decreased in the skin of diabetes patients; interleukin (IL)-6 expression increased, and growth factor-related indexes decreased. ADSCs-hEVs significantly increased the expression and secretion of growth factors, compared with ADSCs-EVs. In vivo, ADSC-hEV treatment accelerated the healing rate and improved the healing quality of diabetic wounds compared with ADSCs-EVs.

CONCLUSION

Speed and quality of wound healing increased significantly in the ADSCs-hEVs group, which could inhibit early inflammation while promoting the secretion and expression of growth factors and extracellular matrix-related indexes.

Fluorescent Light Energy and Chronic Lesions: A Winning Association

Background:

Chronic ulcers represent a challenge for healthcare professionals and a large expense for national health care systems for their difficulty in achieving complete healing and for their high incidence of recurrence. With the progressive aging of the general population, the incidence of these injuries will only increase, further affecting the public health budget, hence the need to find new strategies for their management. The purpose of this study was to share the experience of the Complex Operational Unit of Plastic Surgery of the University Hospital of Padua with fluorescent light energy therapy, outlining its role in the treatment of chronic ulcers in the daily use outside the previous EUREKA study.

Methods:

In this case series study, we enrolled 15 patients with chronic ulcers of any etiology between January 2018 and July 2019 and we treated them using fluorescence light energy. We evaluated efficacy and safety endpoints reporting data in excel files completed by medical staff during the study.

Results:

The study confirms the effectiveness of fluorescent light energy inducing chronic ulcer healing, regardless of etiology, or at least preparing the lesions for a skin graft closure surgery. The system showed a low rate of complications established by patient adherence to treatment. Patients also reported a reduction in pain both at home and during outpatient dressings.

Conclusion:

Based on our experience, fluorescent light energy shows an excellent safety and efficacy profile in chronic ulcers no more responsive to traditional dressings and/or surgery.

Current application and future directions of photobiomodulation in central nervous diseases

Photobiomodulation using light in the red or near-infrared region is an innovative treatment strategy for a wide range of neurological and psychological conditions. Photobiomodulation can promote neurogenesis and elicit anti-apoptotic, anti-inflammatory and antioxidative responses. Its therapeutic effects have been demonstrated in studies on neurological diseases, peripheral nerve injuries, pain relief and wound healing. We conducted a comprehensive literature review of the application of photobiomodulation in patients with central nervous system diseases in February 2019. The NCBI PubMed database, EMBASE database, Cochrane Library and ScienceDirect database were searched. We reviewed 95 papers and analyzed. Photobiomodulation has wide applicability in the treatment of stroke, traumatic brain injury, Parkinson's disease, Alzheimer's disease, major depressive disorder, and other diseases. Our analysis provides preliminary evidence that PBM is an effective therapeutic tool for the treatment of central nervous system diseases. However, additional studies with adequate sample size are needed to optimize treatment parameters.

Treatment of diabetic foot ulcers in a frail population with severe co-morbidities using at-home photobiomodulation laser therapy: a double-blind, randomized, sham-controlled pilot clinical study

PURPOSE

To evaluate the safety and efficacy of an at-home photobiomodulation (PBM) device for the treatment of diabetic foot ulcers (DFUs) in a frail population with severe comorbidities.

METHODS

Prospective, randomized, double-blind, sham-controlled pilot study. Patients (age = 63 ± 11 years, male:female 13:7) with insulin-dependent diabetes type 2, neuropathy, peripheral artery disease, significant co-morbidities, and large osteomyelitis-associated DFUs (University of Texas grade ≥ III) were randomized to receive active (n = 10) or sham (n = 10) at-home daily PBM treatments (pulsed near-infrared 808 nm Ga-Al-As laser, 250 mW, 8.8 J/cm²) for up to 12 weeks in addition to standard care. The primary outcome was the %wound size reduction. The secondary was adverse events.

RESULTS

With the numbers available, PBM-treated group had significantly greater %reduction compared to sham (area [cm²], baseline vs endpoint: PBM 10[20.3] cm² vs 0.2[2.4] cm²; sham, 7.9 [12.0] cm² vs 4.6 [13.8] cm², p = 0.018 by Mann-Whitney U test). Wound closure > 90% occurred in 7 of 10 PBM-treated patients but in only 1 of 10 sham patients (p = 0.006). No adverse device effects were observed.

CONCLUSIONS

Photobiomodulation at home, in addition to standard care, may be effective for the treatment of severe DFUs in frail patients with co-morbidities and is particularly relevant at these times of social distancing. Our preliminary results justify the conduction of a larger clinical trial. ClinicalTrials.gov: NCT01493895.

Photobiomodulation in diabetic wound healing: A review of red and near-infrared wavelength applications

The development of a painless, non-invasive, and faster way to diabetic wound healing is at the forefront of research. The complexity associated with diabetic wounds makes it a cause for concern amongst diabetic patients and the world at large. Irradiation of cells generates a photobiomodulatory response on cells and tissues, directly causing alteration of cellular processes and inducing diabetic wound repair. Photobiomodulation therapy (PBMT) using red and near-infrared (NIR) wavelengths is being considered as a promising technique for speeding up the rate of diabetic wound healing, eradication of pain and reduction of inflammation through the alteration of diverse cellular and molecular processes. This review presents the extent to which the potential of red and NIR wavelengths have been harnessed in PBMT for diabetic wound healing. Important research challenges and gaps are identified and discussed, and future directions mapped out. This review thus provides useful insights and strategies into improvement of PBMT, including its acceptance within the global medical research community.

A study of therapeutic effects of 670 nm irradiation in different types of diabetic macular edema

The purpose of this study was to investigate the therapeutic effects of 670 nm irradiation in patients with diabetic macular edema. In several studies, positive effects of red/near-infrared irradiation showed in a range of ocular diseases such as macular degeneration, macular edema, and retinitis pigmentosa. This study was conducted on forty five eyes of 26 diabetic patients with macular edema between the ages of 51 and 80.

Measurement of visual acuity and slit lamp examination, funduscopy, and optical coherence tomography were performed in all subjects. None of the patients had proliferative retinopathy. We used a portable LED device (Warp 10, Quantum Devices) for treatment. Patients held this device at a distance of 3 cm from their eyes for 240 seconds for three months. Full ophthalmic examinations were repeated 1, 2, and 3 months after treatment.

After 3 months, the mean visual acuity improved from 0.44 ± 0.38 log MAR to 0.27 ± 0.24 log MAR and vision increased by 1.52 ± 1.16 lines post treatment (р<0.001). The mean central macula thickness decreased from 381.49 ± 144.40 μm to 359.72 ± 128.84 μm (р=0.050). In patients with mild and moderate nonproliferative diabetic retinopathy, the mean central retinal thickness decreased 52.06 ± 67.78 μm and 39.27 ± 44.69 μm, respectively, but patients with severe type showed an increase of 34.93 ± 65.65 μm in the mean central retinal thickness (р<0.001). Also, the severity of macular edema had no effect on final outcomes (р>0.05). Photobiomodulation can positively affect diabetic macular edema, especially in patients with mild to moderate diabetic retinopathy.

670 nm photobiomodulation improves the mitochondrial redox state of diabetic wounds

Background

Photobiomodulation (PBM) by far-red (FR) to near-infrared (NIR) light has been demonstrated to accelerate diabetic wound healing in preclinical and clinical studies. Mitochondrial dysfunction and oxidative stress play key roles in impaired diabetic wound healing, and the effect of PBM on the metabolic state of diabetic wounds remains to be elucidated.

Methods

In this study, a custom-designed in vivo fluorescence imaging technique was used to quantitatively assess the effect of FR-PBM on the mitochondrial bioenergetics of diabetic wounds. The intrinsic fluorescence of two mitochondrial co-enzymes, nicotinamide adenine dinucleotide (NADH) and oxidized flavin adenine dinucleotide (FAD), was monitored to quantify the redox ratio (RR) (NADH/FAD) of wounds over time.

Results

Using an excisional model of wound healing, we demonstrated that 670 nm (FR) PBM improved mitochondrial bioenergetics and stimulated the rate of wound healing in diabetic db/db mice. Wound closure and the RR of diabetic wounds in response to 670 nm PBM (4.5 J/cm², 60 mW/cm² for 90 s per day, 5 days/week) were compared to the sham-treated group. At day 9 of post-wounding, we observed a 43% decrease in the wound area and a 75% increase in RR in FR-treated diabetic mice compared to sham-treated diabetic mice.

Conclusions

We conclude that the increase in mitochondrial RR and the related decrease in oxidative stress may be an important factor in FR-PBM mediated acceleration of wound healing in diabetic mice.

Comparison Of The Efficacy Of Two Laser Types In Healing Of Full-Thickness Wound: An Experimental Study

The aim of the study ― To investigate the effectiveness of pulsed laser with high intensity and laser with low intensity on a full-thickness wound in rats and to compare the effects of both laser types. Material and Methods ― Forty-five adult male rats were utilized in the present study. After anesthesia, wound of five cm2 was produced on dorsal aspect in each rat; then, the rats were randomly classified into three groups as follows: high power pulsating laser group (A) which received Nd: YAG laser with 1064 nm wavelength, low power laser group (B) which received GaAlAs laser with 830 nm wavelength, and control group (C) which received no treatment. Laser lights in groups (A) and (B) were introduced at an intensity of five joules per cm2 with a total energy of 25 joules for each wound area through the use of a scanning method and at a rate of 3 sessions per week for three weeks. Results ― At the end of treatment, better wound healing in form of more wound contraction and higher healing rate was elicited in both laser groups in comparison to wound healing in the control group, and there were no significantly different effects between both laser types. Conclusion ― At the intensity of five joules/cm2, both low-intensity and pulsating high-intensity lasers speed up the healing of the wound in rats, and there are no significant differences between their effects.

Photobiomodulation: systematic review and meta-analysis of the most used parameters in the resolution diabetic foot ulcers

The most common photobiomodulation parameters used to aid in the treatment of diabetic foot ulcers were investigated in this paper. The databases MEDLINE, LILACS, MEDCARIB, PAHO-IRIS, and WHOLIS were searched with the following descriptors: diabetic foot ulcers AND low-level laser therapy OR low-level therapy AND wound healing; this search was conducted from January of 2014 to December of 2019. Inclusion criteria were randomized clinical trials on humans. Exclusion criteria were systematic reviews, literature reviews, studies with animals, studies lacking photobiomodulation parameters, and studies with non-diabetic individuals. The Jadad scale was used in order to analyze the methodological quality of the matching papers. There were seventeen studies found on PubMed and four on LILACS. Among these, seven were selected, according to the inclusion and exclusion criteria. Two out of the seven matching studies obtained a high score, and five obtained a low score, on the Jadad scale. The studies settled on the use of 600-nm and 800-nm wavelength spectrum. Most of the analyzed papers on photobiomodulation on diabetic foot ulcers did not describe the detailed parameters in their methodology. None of the studies featured the maximum score with regard to the Jadad scale for methodological quality. The relations of energy versus wavelength and power versus wavelength were divergent among the parameters on the papers. Therefore, it is necessary to analyze the parameters for an optimized power value in order to improve the results of the treatment.

Selective Laser Efficiency of Green-Synthesized Silver Nanoparticles by Aloe arborescens and Its Wound Healing Activities in Normal Wounded and Diabetic Wounded Fibroblast Cells: In vitro Studies

Introduction

Silver nanoparticles (AgNPs) have been extensively used in wound healing applications owing to their valuable physicochemical and biological properties. The main objective of this study was to evaluate the combined effects of green-synthesized silver nanoparticles (G-AgNPs) and photobiomodulation (PBM; laser irradiation at 830 nm with 5 J/cm²) in normal wounded and diabetic wounded fibroblast cells (WS1).

Methods

The combined effect of G-AgNPs and PBM was studied by various in vitro wound healing studies including cell morphology, cell migration rate and percentage wound closure, cell viability, cell proliferation, and filamentous (F)-actin and nuclear morphology staining.

Results

Cell viability results revealed good cellular compatibility of G-AgNPs to WS1 cells. The combined therapy of G-AgNPs and PBM demonstrated promising results to achieve progressive migration and wound closure in both normal wounded and diabetic wounded cell models. G-AgNPs alone and in combination with PBM had no negative effect on cell viability and proliferation, and there was an increase in cell migration.

Conclusion

Overall, these findings demonstrate that the combined treatment of G-AgNPs and PBM does not display any adverse effects on wound healing processes in both normal wounded and diabetic wounded cell models.

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.

Therapeutic advances in wound healing

Wound healing is a complex physiological process that occurs in the human body involving the sequential activation of multiple cell types and signaling pathways in a coordinated manner. Chronic wounds and burns clearly decrease quality of life of the patients since they are associated with an increase in physical pain and socio-economical complications. Furthermore, incidence and prevalence of chronic wounds (unlike burns) have been increasing mainly due to population aging resulting in increased costs for national health systems. Thus, the development of new and more cost-effective technologies/therapies is not only of huge interest but also necessary to improve the long-term sustainability of national health systems. This review covers the current knowledge on recent technologies/therapies for skin regeneration, such as: wound dressings; skin substitutes; exogenous growth factor based therapy and systemic therapy; external tissue expanders; negative pressure; oxygen; shock wave, and photobiomodulation wound therapies. Associated benefits and risks as well as the clinical use and availability are all addressed for each therapy. Moreover, future trends in wound care including novel formulations using metallic nanoparticles and topical insulin are herein presented. These novel formulations have shown to be promising therapeutic options in the near future that may change the wound care paradigm.

Cell-autonomous light sensitivity via Opsin3 regulates fuel utilization in brown adipocytes

Opsin3 (Opn3) is a transmembrane heptahelical G protein–coupled receptor (GPCR) with the potential to produce a nonvisual photoreceptive effect. Interestingly, anatomical profiling of GPCRs reveals that Opn3 mRNA is highly expressed in adipose tissue. The photosensitive functions of Opn3 in mammals are poorly understood, and whether Opn3 has a role in fat is entirely unknown. In this study, we found that Opn3-knockout (Opn3-KO) mice were prone to diet-induced obesity and insulin resistance. At the cellular level, Opn3-KO brown adipocytes cultured in darkness had decreased glucose uptake and lower nutrient-induced mitochondrial respiration than wild-type (WT) cells. Light exposure promoted mitochondrial activity and glucose uptake in WT adipocytes but not in Opn3-KO cells. Brown adipocytes carrying a defective mutation in Opn3’s putative G protein–binding domain also exhibited a reduction in glucose uptake and mitochondrial respiration in darkness. Using RNA-sequencing, we identified several novel light-sensitive and Opn3-dependent molecular signatures in brown adipocytes. Importantly, direct exposure of brown adipose tissue (BAT) to light in living mice significantly enhanced thermogenic capacity of BAT, and this effect was diminished in Opn3-KO animals. These results uncover a previously unrecognized cell-autonomous, light-sensing mechanism in brown adipocytes via Opn3-GPCR signaling that can regulate fuel metabolism and mitochondrial respiration. Our work also provides a molecular basis for developing light-based treatments for obesity and its related metabolic disorders.

Brown adipose tissue plays a pivotal role in energy homeostasis and serves as a metabolic sink for glucose and fatty acid. This study demonstrates a novel light-sensing mechanism in mice via the photoreceptor Opsin3 that regulates fuel utilization and mitochondrial activity of brown adipocytes.

Biomodulation induced by fluorescent light energy versus standard of care in venous leg ulcers: a retrospective study

Objective:

The recently completed EUREKA study confirmed the efficacy and safety profile of fluorescent light energy (FLE) in treating hard-to-heal wounds. To supplement the EUREKA prospective, observational, uncontrolled trial results, researchers selected one of the EUREKA clinical centres to conduct a retrospective analysis of matching wound care data for 46 venous leg ulcers (VLU) patients who had received standard wound care over a five-year period, compared with 10 EUREKA VLU subjects.

Method:

The study centre selected 46 patients with VLUs based on the matching criteria (wound age and size, patient's age and gender). They compared the healing rates of these matching VLUs with 10 VLU patients treated at the same centre during the EUREKA study.

Results:

The EUREKA patients had larger and significantly older wounds (p<0.05) and significantly more risk factors (p<0.05) than the matching wounds. However, they had better outcomes (EUREKA: 40% versus matching group: 7% for full wound closure by 16 weeks). No wound breakdown was observed at 16 weeks in the EUREKA group, compared with 25% in the matching group. No EUREKA patient developed infections requiring antibiotics, compared with 37% in the matching group. EUREKA wounds had a mean relative wound area regression (RWAR) of 32% at week six and 50% at week 16, compared with −3% at week six and −6% at week 16 for the matching group.

Conclusion:

These findings show that the system based on FLE was well-tolerated and efficacious, with better clinical outcome results compared with the wounds analysed in this retrospective matching study and treated with standard of care alone.

Fluorescence Imaging of Mitochondrial Redox State to Assess Diabetic Wounds

Background: Diabetes is known to cause delayed wound healing, and chronic non-healing lower extremity ulcers may end with lower limb amputations and mortalities. Given the increasing prevalence of diabetes mellitus worldwide, it is critical to focus on underlying mechanisms of these debilitating wounds to find novel therapeutic strategies and thereby improve patient outcome. Methods: This study aims to design a label-free optical fluorescence imager that captures metabolic indices (NADH and FAD autofluorescence) and monitors the in vivo wound healing progress noninvasively. Furthermore, 3D optical cryo-imaging of the mitochondrial redox state was utilized to assess the volumetric redox state of the wound tissue. Results: The results from our in vivo fluorescence imager and the 3D cryo-imager quantify the differences between the redox state of wounds on diabetic mice in comparison with the control mice. These metabolic changes are associated with mitochondrial dysfunction and higher oxidative stress in diabetic wounds. A significant correlation was observed between the redox state and the area of the wounds. Conclusion: The results suggest that our developed novel optical imaging system can successfully be used as an optical indicator of the complex wound healing process noninvasively.

Heparin-poloxamer hydrogel-encapsulated rhFGF21 enhances wound healing in diabetic mice

Wound healing, especially for diabetic wounds, is a lengthy and complicated process involving interactions and responses at the protein, cell, and tissue levels. Loading of growth factors into a hydrogel to construct a sustained-release system is considered a promising approach to improve wound healing. The present study investigates the effect of thermosensitive heparin-poloxamer (HP) hydrogel-encapsulated recombinant human fibroblast growth factor 21 (rhFGF21) on wound healing in mice with streptozotocin-induced diabetes mellitus. First, we studied the in vitro release of rhFGF21 from the rhFGF21-HP coacervate. The results showed that HP might control the release of rhFGF21. Next, we examined the effect of rhFGF21-HP on skin wound healing in diabetic mice. Our data showed that rhFGF21-HP significantly improved wound closure; promoted granulation, collagen deposition, and re-epithelialization; and enhanced the expression of CD31. Moreover, rhFGF21-HP had obvious advantages in diabetic wound healing. Therefore, the results suggest that the rhFGF21-HP hydrogel polymer plays an important role in skin wound healing. This work provides a suitable sustained-release delivery system that can continuously release rhFGF21 and presents a promising therapeutic strategy for wound healing in patients with diabetes.-Liu, H., Zhao, Y., Zou, Y., Huang, W., Zhu, L., Liu, F., Wang, D., Guo, K., Hu, J., Chen, J., Ye, L., Li, X., Lin, L. Heparin-poloxamer hydrogel-encapsulated rhFGF21 enhances wound healing in diabetic mice.

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.

Effects of different light spectra on embryo development and the performance of newly hatched turbot (Scophthalmus maximus) larvae

Light is a key environmental factor that synchronizes various life stages from embryo development to sexual maturation in fish. For turbot, light spectra have the most influence at the larval and juvenile stages. In the current study, differences in the development of embryos and the performance of newly hatched turbot larvae exposed to five different spectra: full spectrum (LDF), blue (LDB, peak at 450 nm), green (LDG, peak at 533 nm), orange (LDO, peak at 595 nm) and red (LDR, peak at 629 nm), were examined. At 62.8 h post fertilization, a higher number of embryos exposed to short-wavelengths (LDG and LDB) had developed a heartbeat in comparison with embryos exposed to other wavelengths. Larvae exposed to the green spectrum had higher malformation rates than larvae exposed to the other spectra, indicating that larvae exposed to green light may have significantly reduced survival rates. The results of non-specific immunity parameters showed that the mRNA expression levels of cathepsin D (CTSD), cathepsin F (CTSF), catalase (CAT) and metallothionein (MT) in larvae exposed to LDB were significantly higher than those exposed to other spectra, but CAT activity in larvae exposed to LDB was significantly lower than larvae exposed to the other spectra. There was no significant difference in MT activity in larvae exposed to the five different spectra. The mRNA expression level of lysozyme (LZM) in larvae exposed to LDR was significantly higher than other spectra, while there was no significant difference in LZM activity observed in larvae exposed to LDR, LDG, LDB and LDF. The difference of the enzyme activity of total superoxide dismutase (T-SOD) was not significant among larvae exposed to the five spectra. mRNA expression of the heat shock protein 70 (HSP70) was significantly higher in newly hatched larvae exposed to LDB, LDR and LDG, indicating that larvae exposed to LDB, LDG and LDR exhibited a stress response. The mRNA expression level of the insulin-like growth factor-1 (IGF-1) and growth parameters in the newly hatched larvae exposed to the different spectra were not significantly different. The results of the present study indicate that LDO and LDF should be used for embryo incubation and newly hatched larvae when rearing turbot. This study provides a theoretical basis for optimizing the incubation light environment for fertilized turbot eggs, promoting immunity and reducing stress responses in newly hatched larvae.

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.

Effects of low-level laser therapy on the healing of surgically closed incisions and surgically created open wounds in dogs

OBJECTIVE

To determine the effects of low-level laser therapy (LLLT) on primarily closed incisions and full thickness open wounds in dogs.

STUDY DESIGN

Prospective, masked, placebo-controlled design.

ANIMAL POPULATION

Healthy intact female dogs (n = 10).

METHODS

Dogs underwent bilateral flank ovariectomy procedures, and open wounds were created bilaterally with a punch biopsy. Each side of the dog (incision and open wound) was randomly assigned to the treatment (TX) group or the control (CN) group. The TX group received LLLT once daily for 5 days with a 980-nm laser and a total energy density of 5 J/cm² . The CN group received a sham treatment (laser turned off) for an identical amount of time each day. The wounds were assessed visually; measured; photographed at postoperative days 3, 7, 11, and 14; and biopsied on postoperative days 7 and 14. A 2-way repeated measures multivariate analysis of variance was used to analyze differences between groups.

RESULTS

There was no difference between groups for subjective assessment of healing time and wound measurements (P = .7). There was no difference in histopathologic assessment except that the CN group had more necrosis and perivascular lymphocytes and macrophages at day 7 (P = .03). The TX group had more perivascular lymphocytes and macrophages at day 14 (P = .01).

CONCLUSION

LLLT did not appear to influence the healing of surgically created incisions and small wounds with the methodology reported here.

CLINICAL SIGNIFICANCE

Results of this study do not support recommending LLLT to stimulate healing of uncomplicated, small wounds and incisions.

The effects of exercise training associated with low-level laser therapy on biomarkers of adipose tissue transdifferentiation in obese women

Investigations suggest the benefits of low-level laser therapy (LLLT) to improve noninvasive body contouring treatments, inflammation, insulin resistance and to reduce body fat. However, the mechanism for such potential effects in association with exercise training (ET) and possible implications in browning adiposity processes remains unclear. Forty-nine obese women were involved, aged between 20 and 40 years with a body mass index (BMI) of 30-40 kg/m². The volunteers were divided into Phototherapy (808 nm) and SHAM groups. Interventions consisted of exercise training and phototherapy applications post exercise for 4 months, with three sessions/week. Body composition, lipid profile, insulin resistance, atrial natriuretic peptide (ANP), WNT5 signaling, interleukin-6 (IL-6), and fibroblast growth factor-21 (FGF-21) were measured. Improvements in body mass, BMI, body fat mass, lean mass, visceral fat, waist circumference, insulin, HOMA-IR, total cholesterol, LDL-cholesterol, triglycerides, and ANP in both groups were demonstrated. Only the Phototherapy group showed a reduction in interleukin-6 and an increase in WNT5 signaling. In addition, it was possible to observe a higher magnitude change for the fat mass, insulin, HOMA-IR, and FGF-21 variables in the Phototherapy group. In the present investigation, it was demonstrated that exercise training associated with LLLT promotes an improvement in body composition and inflammatory processes as previously demonstrated. The Phototherapy group especially presented positive modifications of WNT5 signaling, FGF-21, and ANP, possible biomarkers associated with browning adiposity processes. This suggests that this kind of intervention promotes results applicable in clinical practice to control obesity and related comorbidities.

Effect of two different commercially available white light LED fixtures on broiler hatchability and chick quality

1. The objective of this study was to evaluate the effect of two different spectra of white light on hatchability and chick quality of broiler chickens. 2. A total of 8424 Ross 708 broiler eggs were divided over three light exposure treatments during incubation: No light (DARK), a light emitting diode (LED) light with high levels of blue light (BLUE), or a LED light with high levels of red light (RED). Hatchability, embryo mortality and chick quality were assessed at hatch. 3. DARK had a higher percentage of chicks with unhealed navels (21.1 ± 1.3%) and fewer overall chicks with no defects (77.0 ± 1.2%) compared to both the BLUE (9.9 ± 0.9% and 88.4 ± 1.1%) and RED treatments (7.7 ± 0.8% and 90.2 ± 1.0%). 4. Both the BLUE (80.9 ± 1.0%) and RED treatments (82.9 ± 1.4%) had higher hatchability of fertile eggs than the DARK treatment (76.0 ± 2.2%). 5. These results indicate that either of these LED fixtures could be used to improve hatchability and chick quality in broiler chickens. Utilising these types of lightings in commercial hatcheries will improve the efficiency via increased hatchability and quality of the chicks hatched.

Dysregulation of wound healing mechanisms in diabetes and the importance of negative pressure wound therapy (NPWT)

Diabetes is a serious disease with severe side effects and comorbidities. Diabetic foot with its chronic nonhealing ulcers, or diabetic foot ulcers, as they are commonly called, can be devastating, even leading to amputation. Many therapies exist to assist and improve wound healing. One exciting discovery is the use of negative pressure wound therapy (NPWT) as an adjunct to standard treatment. Few studies have substantively explored the molecular mechanisms of NPWT and why we see improved wound healing, a concept that demands more research. The following commentary summarizes the current literature regarding NPWT as well as some of the vast body of work that focuses on the physiologic mechanisms of wound healing in diabetics in general.

Can regenerative medicine and nanotechnology combine to heal wounds? The search for the ideal wound dressing

Skin is the outermost covering of the human body and at the same time the largest organ comprising 15% of body weight and 2 m2 surface area. Skin plays a key role as a barrier against the outer environment depending on its thickness, color and structure, which differ from one site to another. The four major types of problematic wounds include ulcers (diabetic, venous, pressure) and burn wounds. Developing novel dressings helps us to improve the wound healing process in difficult patients. Recent advances in regenerative medicine and nanotechnology are revolutionizing the field of wound healing. Antimicrobial activity, exogenous cell therapy, growth factor delivery, biodegradable and biocompatible matrix construction, all play a role in hi-tech dressing design. In the present review, we discuss how the principles of regenerative medicine and nanotechnology can be combined in innovative wound dressings.

Effectiveness of combined laser-puncture and conventional wound care to accelerate diabetic foot ulcer healing

Background: Impaired wound healing is a common complication of diabetes. It has complex pathophysiologic mechanisms and often necessitates amputation. Our study aimed to evaluate the effectiveness of combined laser-puncture and conventional wound care in the treatment of diabetic foot ulcers.Methods: This was a double-blind controlled randomized clinical trial on 36 patients, conducted at the Metabolic Endocrine Outpatient Clinic, Cipto Mangunkusumo Hospital, Jakarta, between May and August 2015. Stimulation by laser-puncture (the treatment group) or sham stimulation (the control group) were performed on top of the standard wound care. Laser-puncture or sham were done on several acupuncture points i.e. LI4 Hegu, ST36 Zusanli, SP6 Sanyinjiao and KI3 Taixi bilaterally, combined with irradiation on the ulcers itself twice a week for four weeks. The mean reduction in ulcer sizes (week 2–1, week 3–1, week 4–1) were measured every week and compared between the two groups and analyzed by Mann-Whitney test.Results: The initial median ulcer size were 4.75 (0.10–9.94) cm2 and 2.33 (0.90–9.88) cm2 in laser-puncture and sham groups, respectively (p=0.027). The median reduction of ulcer size at week 2–1 was -1.079 (-3.25 to -0.09) vs -0.36 (-0.81 to -1.47) cm2, (p=0.000); at week 3–1 was -1.70 (-3.15 to -0.01) vs -0.36 (-0.80 to -0.28) cm2, (p=0.000); and at week 4–1 was -1.22 (-2.72 to 0.00) vs -0.38 (-0.74 to -0.57) cm2, (p=0.012).Conclusion: Combined laser-puncture and conventional wound care treatment are effective in accelerating the healing of diabetic foot ulcer.

Insulin treatment prevents wounding associated changes in tissue and circulating neutrophil MMP-9 and NGAL in diabetic rats

Neutrophils are important for wound repair, but their persistence can impair the healing process. Neutrophils express matrix metalloproteinases including MMP-9 and its regulator neutrophil gelatinase associated lipocalin (NGAL). Whether wounding affects neutrophil MMP-9 and NGAL in diabetic animals is not known. Skin wound tissue MMP-9 and NGAL was examined by qRT-PCR and immunohistochemistry in control, diabetic and insulin treated diabetic rats. The temporal expression of MMP-9 and NGAL mRNA, MMP-9 activity and the NGAL/MMP-9 complex was also investigated in an implant model and their circulating neutrophils. The cellular localisation of MMP-9 and NGAL was confirmed by immunofluorescence and the ability of glucose to regulate these factors was examined in isolated neutrophils. In skin wound tissue compared with control, diabetes increased neutrophil infiltration, NGAL mRNA and MMP-9 protein (P<0.05). Diabetes significantly increased implant neutrophil NGAL and MMP-9 protein as well as NGAL mRNA, wound fluid NGAL/MMP-9 complex and MMP-9 activity (all <0.05). Circulating neutrophil MMP-9 and NGAL was also increased in these diabetic animals (P<0.05). These changes were prevented by insulin treatment. Ex vivo, high glucose (25mM) increased neutrophil NGAL and MMP-9 (both by 2 fold, P<0.05). NGAL and MMP-9 are increased in wound and circulating neutrophils in diabetic rodents. These changes and the association between higher NGAL and increased wound fluid MMP-9 activity suggest that increased neutrophil NGAL may contribute to increased MMP-9 in poorly healing diabetic wounds. Whether targeting neutrophil NGAL or MMP-9 can improve diabetic wound healing remains to be investigated.

Complement Activation and STAT4 Expression Are Associated with Early Inflammation in Diabetic Wounds

Diabetic non-healing wounds are a major clinical problem. The mechanisms leading to poor wound healing in diabetes are multifactorial but unresolved inflammation may be a major contributing factor. The complement system (CS) is the most potent inflammatory cascade in humans and contributes to poor wound healing in animal models. Signal transducer and activator of transcription 4 (STAT4) is a transcription factor expressed in immune and adipose cells and contributes to upregulation of some inflammatory chemokines and cytokines. Persistent CS and STAT4 expression in diabetic wounds may thus contribute to chronic inflammation and delayed healing. The purpose of this study was to characterize CS and STAT4 in early diabetic wounds using db/db mice as a diabetic skin wound model. The CS was found to be activated early in the diabetic wounds as demonstrated by increased anaphylatoxin C5a in wound fluid and C3-fragment deposition by immunostaining. These changes were associated with a 76% increase in nucleated cells in the wounds of db/db mice vs.

CONTROLS

The novel classical CS inhibitor, Peptide Inhibitor of Complement C1 (PIC1) reduced inflammation when added directly or saturated in an acellular skin scaffold, as reflected by reduced CS components and leukocyte infiltration. A significant increase in expression of STAT4 and the downstream macrophage chemokine CCL2 and its receptor CCR2 were also found in the early wounds of db/db mice compared to non-diabetic controls. These studies provide evidence for two new promising targets to reduce unresolved inflammation and to improve healing of diabetic skin wounds.

Photobiomodulation and the brain: a new paradigm

Transcranial photobiomodulation (PBM) also known as low level laser therapy (tLLLT) relies on the use of red/NIR light to stimulate, preserve and regenerate cells and tissues. The mechanism of action involves photon absorption in the mitochondria (cytochrome c oxidase), and ion channels in cells leading to activation of signaling pathways, up-regulation of transcription factors, and increased expression of protective genes. We have studied PBM for treating traumatic brain injury (TBI) in mice using a NIR laser spot delivered to the head. Mice had improved memory and learning, increased neuroprogenitor cells in the dentate gyrus and subventricular zone, increased BDNF and more synaptogenesis in the cortex. These highly beneficial effects on the brain suggest that the applications of tLLLT are much broader than at first conceived. Other groups have studied stroke (animal models and clinical trials), Alzheimer's disease, Parkinson's disease, depression, and cognitive enhancement in healthy subjects.

Ameliorative effect of dietary genistein on diabetes induced hyper-inflammation and oxidative stress during early stage of wound healing in alloxan induced diabetic mice

Among the diabetic complications, diabetic foot ulcer due to delayed wound healing is one of the most significant clinical problems. Early inflammatory stage is important for better prognosis during wound healing. Thus, regulation of inflammatory response during early stage of wound healing is main target for complete cutaneous recovery. This study investigated the role of genistein supplementation in inflammation and oxidative stress, which are related to NLRP3 inflammasome, NFκB and Nrf2 activation, during cutaneous wound healing in alloxan-induced diabetic mice. Mice with diabetes with fasting blood glucose (FBG) levels > 250 mg/dl were fed diets with AIN-93G rodent diet containing 0%, 0.025% (LG) or 0.1% (HG) genistein. After 2 weeks of genistein supplementation, excisional wounds were made by biopsy punches (4 mm). Genistein supplementation improved fasting glucose levels and wound closure rate. Moreover, genistein supplementation restored NLRP3 inflammasome (NLRP3, ASC and caspase-1) at the basal level and ameliorated both inflammation (TNFα, iNOS, COX2 and NFκB) and antioxidant defense system (Nrf2, HO-1, GPx, and catalase) during early stage of wound healing in diabetic mice. Taken together, genistein supplementation would be a potential therapeutic nutrient in prevention and treatment of delayed wound healing by modulation of inflammation and oxidative stress during inflammatory stage.

Laser therapy in wound healing associated with diabetes mellitus - Review

OBJECTIVE

To determine the most effective parameter in healing wounds related to diabetes mellitus, as well as the most widely used type of laser.

METHODOLOGY

consisted of bibliographic searching the databases Bireme, SciELO, PubMed/Medline and Lilacs by using the keywords related to the topic. Were selected from these keywords, papers discussing the use of laser on wounds associated with diabetes, published in the period 2005-2014, in Portuguese or English.

RESULTS

After analyzing the research, 12 studies consistent with the theme were selected.

CONCLUSION

Based on this review, the studies that showed more satisfactory results in healing diabetic wounds were those who applied energy densities in the range of 3-5 J/cm2, power densities equal to or below 0.2 W/cm2 and continuous emission. The He-Ne laser with a wavelength of 632.8 nm was used more often.

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.