A Low-Level Carbon Dioxide Laser Promotes Fibroblast Proliferation and Migration through Activation of Akt, ERK, and JNK

Effectiveness of low-level laser therapy in reducing pain score and healing time of recurrent aphthous stomatitis: a systematic review and meta-analysis

BACKGROUND

Recurrent aphthous stomatitis (RAS) is a common chronic inflammatory oral disease that negatively impacts the quality of life. Current therapies aim to reduce pain and healing process yet challenges such as rapid loss due to salivary flushing in topical drugs and adverse effects due to prolonged use of systemic medications require further notice. Low-level laser therapy is reported with immediate pain relief and faster healing thus preserving the potential for optimal treatment modalities. This review critically analyses and summarizes the effectiveness of LLLT in reducing pain scores and healing time of RAS.

METHODS

A systematic search was conducted in ScienceDirect, PubMed, and Scopus using keywords of low-level laser therapy, photo-biomodulation therapy, and recurrent aphthous stomatitis. RCTs between 1967 to June 2022, presenting characteristics of the laser and reporting pain score and/or healing time of RAS after irradiation were included. Animal studies and recurrent aphthous ulcers with a history of systemic conditions were excluded. Studies were critically appraised using the RoB 2 tool. A meta-analysis was performed using inverse variance random effects.

RESULTS

Fourteen trials with a total of 664 patients were included. Reduced pain was reported in 13 studies, while shortened healing time was presented in 4. The pooling of two studies after CO2 irradiation demonstrated faster healing time compared to placebo (MD - 3.72; 95% CI - 4.18, - 3.25).

CONCLUSION

Pain score and healing time of RAS were reduced after irradiation with LLLT. RoB resulted in "some concerns" urging well-designed RCTs with larger samples to further assess each laser application for comparison.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022355737.

Use of carbon dioxide fractional laser in the management of lower limb ischemia in patients with diabetes: a case report : CO2 fractional laser in the treatment of diabetic foot

Treatment of lower limb ischemia in patients with diabetes is challenging because of the location of the ulcers and the complexity of their pathogenesis. Carbon dioxide fractional laser (CO2FL) therapy in conjunction with tibial periosteum distraction could become a substitute for conventional methods. We herein describe a patient diagnosed with ischemic diabetic foot with a complex ulcer in the upper third of the tibia. Laser irradiation (Deep FX mode with 30 mJ of energy and 10% density) was applied to the entire region of skin below the knee after surface anesthesia, and this treatment was performed twice a week until the ulcer healed. Computed tomography angiography showed successful establishment of a blood supply to the back of the right foot after treatment. Skin grafting was successfully performed, with only a few wounds remaining on the foot 8 months after treatment. The pain score was significantly decreased at the last follow-up. No complications occurred. This case report provides guidance for the performance of CO2FL, a fast, easy, accurate treatment in patients with diabetes. CO2FL can target lower limb arterial occlusive disease accompanied by refractory ulcers, addressing the underlying vascular occlusion and dysfunction as well as promoting microcirculation and wound healing.

Fractional ablative CO2 laser and oral isotretinoin-A prospective randomized controlled split-face trial comparing concurrent versus delayed laser treatment for acne scars

BACKGROUND

Therapeutic dogma has been to treat acne scars with ablative fractional laser no less than 6 months after isotretinoin (ITN) cessation.

OBJECTIVE

To evaluate the safety and efficacy of fractional ablative CO2 laser (FACL) in patients treated concurrently with ITN.

METHODS

We conducted a prospective split-face randomized control trial in patients treated with FACL concurrently with ITN versus patients treated with FACL 6 months post-ITN treatment. Patients received 3 monthly sessions of FACL with concurrent ITN treatment on half of the face; the other side of the face received the same FACL treatment regimen 6 months post-ITN cessation. Patients were followed for adverse effects up to 6 months post-FACL treatment. Final cosmesis was scored using the Quantitative Global Acne Scarring Grading System (GASGS) by three independent dermatologists.

RESULTS

The GASGS of the concurrent ITN-FACL treated side of the face was significantly lower than the side treated with delayed laser therapy (4.7 ± 2.5 vs. 7.7 ± 2.9, respectively, p < 0.001).

LIMITATIONS

The laser's settings were standardized, and not adjusted per patient skin type.

CONCLUSION

Per our prospective trial, concurrent treatment of FACL -ITN is superior to delayed FACL treatment 6 months post-ITN cessation. Fractional ablative laser treatment is effective in improving acne scars, which persist despite isotretinoin therapy.

The Effects and Mechanisms of PBM Therapy in Accelerating Orthodontic Tooth Movement

Malocclusion is one of the three major diseases, the incidence of which could reach 56% of the imperiled oral and systemic health in the world today. Orthodontics is still the primary method to solve the problem. However, it is clear that many orthodontic complications are associated with courses of long-term therapy. Photobiomodulation (PBM) therapy could be used as a popular way to shorten the course of orthodontic treatment by nearly 26% to 40%. In this review, the efficacy in cells and animals, mechanisms, relevant cytokines and signaling, clinical trials and applications, and the future developments of PBM therapy in orthodontics were evaluated to demonstrate its validity. Simultaneously, based on orthodontic mechanisms and present findings, the mechanisms of acceleration of orthodontic tooth movement (OTM) caused by PBM therapy were explored in relation to four aspects, including blood vessels, inflammatory response, collagen and fibers, and mineralized tissues. Also, the cooperative effects and clinical translation of PBM therapy in orthodontics have been explored in a growing numbers of studies. Up to now, PBM therapy has been gaining popularity for its non-invasive nature, easy operation, and painless procedures. However, the validity and exact mechanism of PBM therapy as an adjuvant treatment in orthodontics have not been fully elucidated. Therefore, this review summarizes the efficacy of PBM therapy on the acceleration of OTM comprehensively from various aspects and was designed to provide an evidence-based platform for the research and development of light-related orthodontic tooth movement acceleration devices.

Suppression of matrix degradation and amelioration of disc degeneration by a 970-nm diode laser via inhibition of the p38 MAPK pathway in a rabbit model

Intervertebral disc degeneration (IVDD) mainly manifests as an imbalance between the synthesis and degradation of cellular and extracellular matrix (ECM) components. The cytokine interleukin (IL)-1β-induced inflammatory response of intervertebral discs causes ECM degradation. The aim of this study was to investigate the effects of a 970-nm diode laser therapy (DLT) on inflammatory cytokine IL-1β and ECM degradation proteinases in nucleus pulposus (NP) tissues in a puncture-induced rabbit IVDD model. Thirty-six New Zealand white rabbits were randomly divided into six groups: the normal group, IVDD group, laser group, sham laser group, IVDD + anisomycin (p38MAPK signaling pathway agonist), and laser + anisomycin group. Effects of laser on IVDD progression were detected using radiographic and magnetic resonance imaging. Hematoxylin and eosin, Alcian blue, safranin O-fast green staining, western blotting, and immunohistochemistry staining were performed for the histological analysis and molecular mechanism underlying protection against puncture-induced matrix degradation in NP tissues by DLT. DLT reduced the degree of disc degeneration in the gross anatomy of the disc and increased the T2-weighted signal intensity of NP. Inflammatory cytokine IL-1β levels in the disc were significantly reduced after DLT suppressed the matrix-degrading proteinases MMP13 and ADAMTS-5 and upregulated the protein expression of collagen II and aggrecan. Moreover, it inhibited the p38MAPK signaling pathway in NP tissues in a puncture-induced rabbit IVDD model. DLT reduced puncture-induced overexpression of inflammatory cytokines, mainly IL-1β, thus inhibiting matrix degeneration of NP tissues and ameliorating IVDD. This may be related to inhibition of the p38 MAPK signaling pathway.

Hormesis: wound healing and fibroblasts

Hormetic dose responses are reported here to occur commonly in the dermal wound healing process, with the particular focus on cell viability, proliferation, migration and collagen deposition of human and murine fibroblasts with in vitro studies. Hormetic responses were induced by a wide range of substances, including endogenous agents, pharmaceutical preparations, plant-derived extracts including many well-known dietary supplements, as well as physical stressor agents such as low-level laser treatments. Detailed mechanistic studies have identified common signaling pathways and their cross-pathway communications that mediate the hormetic dose responses. These findings complement and extend a similar comprehensive assessment concerning the occurrence of hormetic dose responses in keratinocytes. These findings demonstrate the generality of the hormetic dose response for key wound healing endpoints, suggesting that the hormesis concept has a fundamental role in wound healing, with respect to guiding strategies for experimental evaluation as well as therapeutic applications.

Comparison of Pulsed and Continuous Wave Diode Laser at 940 nm on the Viability and Migration of Gingival Fibroblasts

Gingival fibroblasts have critical roles in oral wound healing. Photobiomodulation (PBM) has been shown to promote mucosal healing and is now recommended for managing oncotherapy-associated oral mucositis. This study examined the effects of the emission mode of a 940 nm diode laser on the viability and migration of human gingival fibroblasts. Cells were cultured in a routine growth media and treated with PBM (average power 0.1 W/cm² , average fluence 3 J/cm² , every 12h for 6 sessions) in one continuous wave (CW) and two pulsing settings with 20 % and 50 % duty cycles. Cell viability was assessed using MTT, and digital imaging quantified cell migration. After 48 and 72 hours, all treatment groups had significantly higher viability (n = 6, p < 0.05) compared to the control. The highest viability was seen in the pulsed (20% duty cycle) group at the 72-hour time point. PBM improved fibroblast migration in all PBM-treated groups, but differences were not statistically significant (n = 2, p > 0.05). PBM treatments can promote cell viability in both continuous and pulsed modes. Further studies are needed to elucidate the optimal setting for PBM-evoked responses for its rationalized use in promoting specific phases of oral wound healing.

Regulatory Processes of the Canonical Wnt/β-Catenin Pathway and Photobiomodulation in Diabetic Wound Repair

Skin is a biological system composed of different types of cells within a firmly structured extracellular matrix and is exposed to various external and internal insults that can break its configuration. The restoration of skin's anatomic continuity and function following injury is a multifaceted, dynamic, well-coordinated process that is highly dependent on signalling pathways, including the canonical Wnt/β catenin pathway, all aimed at restoring the skin's protective barrier. Compromised and inappropriate tissue restoration processes are often the source of wound chronicity. Diabetic patients have a high risk of developing major impediments including wound contamination and limb amputation due to chronic, non-healing wounds. Photobiomodulation (PBM) involves the application of low-powered light at specific wavelengths to influence different biological activities that incite and quicken tissue restoration. PBM has been shown to modulate cellular behaviour through a variety of signal transduction pathways, including the Wnt/β catenin pathway; however, the role of Wnt/β catenin in chronic wound healing in response to PBM has not been fully defined. This review largely focuses on the role of key signalling pathways in human skin wound repair, specifically, the canonical Wnt/β-catenin pathway, and the effects of PBM on chronic wound healing.

Method to analyze effects of low-level laser therapy on biological cells with a digital holographic microscope

Low-level laser therapy (LLLT) is a therapeutic tool that uses the photobiochemical interaction between light and tissue. Its effectiveness is controversial due to a strong dependence on dosimetric parameters. In this work, we demonstrate that digital holographic microscopy is an effective label-free imaging technique to analyze the effects of LLLT on biological cells, and we propose the full methodology to create correct synthetic aperture phase maps for further extensive, highly accurate statistical analysis. The proposed methodology has been designed to provide a basis for many other biological experiments using quantitative phase imaging. We use SHSY-5Y and HaCaT cells irradiated with different doses of red light for the experiment. The analysis shows quantitative changes in cell dry mass density and the projected cell surface in response to different radiation doses.

Luteolin potentiates low-dose oxaliplatin-induced inhibitory effects on cell proliferation in gastric cancer by inducing G2/M cell cycle arrest and apoptosis

Although the reduction of oxaliplatin doses may alleviate deleterious side effects of gastrointestinal and gynecological cancer treatment, it also limits the anticancer therapeutic effects. As a high-efficient and low-priced herbal medicine ingredient, luteolin is an agent with a broad spectrum of anticancer activities and acts as a potential enhancer of therapeutic effects of chemotherapy agents in cancer treatment. This study focused on the antitumor effects and mechanism of combined treatment with luteolin and oxaliplatin on a mouse forestomach carcinoma (MFC) cell line. The study used CCK-8 assay, flow cytometry, Annexin V-FITC/PI double staining assay, reactive oxygen species testing assay, mitochondrial membrane potential testing assay, and western blot assay. The results showed that luteolin and oxaliplatin exerted synergistic effects on inhibiting MFC cell proliferation by inducing G₂/M cell cycle arrest and apoptosis. Inhibiting the tumor necrosis factor receptor-associated protein 1/phosphorylated-extracellular-regulated protein kinases1/2/cell division cycle 25 homolog C/cyclin-dependent kinase-1/cyclin B1 pathway was indispensable to the combined treatment with luteolin and oxaliplatin to induce G₂/M cell cycle arrest. In addition, luteolin increased oxidative stress in MFC cells treated with a low dose of oxaliplatin. The combined therapy damaged mitochondrial membrane potential and regulated BCL-2-associated X protein and B-cell lymphoma 2 protein expression, leading to apoptosis. Findings of the present study suggest that luteolin may be a qualified chemotherapy enhancer to potentiate the anticancer effects of low-dose oxaliplatin in MFC cells. This work provides a theoretical foundation for future research on applications of luteolin in clinical chemotherapy.

Efficacy and safety of CO2 laser in the treatment of chronic wounds: A Retrospective Matched Cohort Trial

OBJECTIVES

Treating chronic cutaneous wounds is challenging, and debridement is a central concept in treating them. Studies have shown that CO₂ laser debridement can control local infection and promote the wound healing process. The present study aimed to investigate the efficacy and safety of fully ablative CO₂ laser debridement compared to routine surgical debridement in the treatment of chronic wounds.

METHODS

The retrospective cohort study was conducted on patients with chronic (>1 month) cutaneous wounds (≥1 cm² ) between December 1, 2017, and December 1, 2020, in the Wound Healing Center at Shanghai Ruijin Hospital, China. Patients treated with CO₂ laser debridement with a DEKA SmartXide2 C80 (DEKA) (the CO₂ laser group) were compared with matched control patients with similar baseline characteristics who had undergone routine surgical debridement (the routine group). The primary outcome was time-to-heal (days) for chronic wounds in two groups, and secondary outcomes included the wound area and BWAT (Bates-Jensen wound assessment tool) score before treatment, and at 1, 2, 3, and 4 weeks after treatment.

RESULTS

The study included 164 patients (82 in the CO₂ laser group and 82 matched in the routine group). The time-to-heal for patients in the CO₂ laser group (41.30 ± 17.11) was significantly shorter than that of the patients in the routine group (48.51 ± 24.32) (p = 0.015). At 3 and 4 weeks after treatment, the absolute wound area of the CO₂ laser group was significantly smaller than that of the routine group. Also, the CO₂ laser group exhibited a significantly lower relative area at 2, 3, and 4 weeks after treatment. The CO₂ laser group yielded significantly lower BWAT scores at 2, 3, and 4 weeks after treatment. Additionally, the relative BWAT score was significantly lower in the CO₂ laser group than the relative scores in the routine group at 2, 3, and 4 weeks after treatment. No adverse events related to the treatments were observed in either group during the study period.

CONCLUSIONS

The present study has shown that fully ablative CO₂ laser debridement has several advantages over routine sharp surgical debridement. It is superior at ameliorating wound status and reducing wound area, and it also significantly reduces the time-to-heal for chronic wounds, without causing any adverse events.

Cellular Signalling and Photobiomodulation in Chronic Wound Repair

Photobiomodulation (PBM) imparts therapeutically significant benefits in the healing of chronic wounds. Chronic wounds develop when the stages of wound healing fail to progress in a timely and orderly frame, and without an established functional and structural outcome. Therapeutic benefits associated with PBM include augmenting tissue regeneration and repair, mitigating inflammation, relieving pain, and reducing oxidative stress. PBM stimulates the mitochondria, resulting in an increase in adenosine triphosphate (ATP) production and the downstream release of growth factors. The binding of growth factors to cell surface receptors induces signalling pathways that transmit signals to the nucleus for the transcription of genes for increased cellular proliferation, viability, and migration in numerous cell types, including stem cells and fibroblasts. Over the past few years, significant advances have been made in understanding how PBM regulates numerous signalling pathways implicated in chronic wound repair. This review highlights the significant role of PBM in the activation of several cell signalling pathways involved in wound healing.

Cyclometalated Ru(II) β-carboline complexes induce cell cycle arrest and apoptosis in human HeLa cervical cancer cells via suppressing ERK and Akt signaling

Two new cyclometalated Ru(II)-β-carboline complexes, [Ru(dmb)₂(Cl-Ph-βC)](PF₆) (dmb = 4,4'-dimethyl-2,2'-bipyridine; Cl-Ph-βC = Cl-phenyl-9H-pyrido[3,4-b]indole; RuβC-3) and [Ru(bpy)₂(Cl-Ph-βC)](PF₆) (bpy = 2,2'-bipyridine; RuβC-4) were synthesized and characterized. The Ru(II) complexes display high cytotoxicity against HeLa cells, the stabilized human cervical cancer cell, with IC₅₀ values of 3.2 ± 0.4 μM (RuβC-3) and 4.1 ± 0.6 μM (RuβC-4), which were considerably lower than that of non-cyclometalated Ru(II)-β-carboline complex [Ru(bpy)₂(1-Py-βC)] (PF₆)₂ (61.2 ± 3.9 μM) by 19- and 15-folds, respectively. The mechanism studies indicated that both Ru(II) complexes could significantly inhibit HeLa cell migration and invasion, and effectively induce G0/G1 cell cycle arrest. The new Ru(II) complexes could also trigger apoptosis through activating caspase-3 and poly (ADP-ribose) polymerase (PARP), increasing the Bax/Bcl-2 ratio, enhancing reactive oxygen species (ROS) generation, decreasing mitochondrial membrane potential (MMP), and inducing cytochrome c release from mitochondria. Further research revealed that RuβC-3 could deactivate the ERK/Akt signaling pathway thus inhibiting HeLa cell invasion and migration, and inducing apoptosis. In addition, RuβC-3-induced apoptosis in HeLa cells was closely associated with the increase of intracellular ROS levels, which may act as upstream factors to regulate ERK and Akt pathways. More importantly, RuβC-3 exhibited low toxicity on both normal BEAS-2B cells in vitro and zebrafish embryos in vivo. Consequently, the developed Ru(II) complexes have great potential on developing novel low-toxic anticancer drugs.

Mesenchymal stem cells in osteoarthritis therapy: a review

Osteoarthritis (OA) is a chronic joint disease that generally occurs worldwide with pain and disability. The progression is slow, and it is mostly diagnosed midlife and often disturbs the knees, hips, feet, hands, and spine. Sex, age, obesity, occupation, and hereditary factors are risk factors that increase the opportunity for OA. Physical examinations involving X-rays and MRI, joint fluid analysis and blood tests are common tools for the diagnosis of OA. Interventions including exercise, manual therapy, lifestyle modification, and medication can help relieve pain and maintain mobility in the affected joints, yet none of the therapies enables the promotion of regeneration of degenerated tissues. Mesenchymal stem cells (MSCs) are a promising source for the treatment of OA due to their multipotency for differentiation into chondrocytes and their ability to modulate the immune system. Herein, we review the pathogenesis and treatment of OA and address the current status of MSCs as a novel potential therapeutic agent in OA treatment.

In Vitro Cytological Responses against Laser Photobiomodulation for Periodontal Regeneration

Periodontal disease is a chronic inflammatory disease caused by periodontal bacteria. Recently, periodontal phototherapy, treatment using various types of lasers, has attracted attention. Photobiomodulation, the biological effect of low-power laser irradiation, has been widely studied. Although many types of lasers are applied in periodontal phototherapy, molecular biological effects of laser irradiation on cells in periodontal tissues are unclear. Here, we have summarized the molecular biological effects of diode, Nd:YAG, Er:YAG, Er,Cr:YSGG, and CO₂ lasers irradiation on cells in periodontal tissues. Photobiomodulation by laser irradiation enhanced cell proliferation and calcification in osteoblasts with altering gene expression. Positive effects were observed in fibroblasts on the proliferation, migration, and secretion of chemokines/cytokines. Laser irradiation suppressed gene expression related to inflammation in osteoblasts, fibroblasts, human periodontal ligament cells (hPDLCs), and endothelial cells. Furthermore, recent studies have revealed that laser irradiation affects cell differentiation in hPDLCs and stem cells. Additionally, some studies have also investigated the effects of laser irradiation on endothelial cells, cementoblasts, epithelial cells, osteoclasts, and osteocytes. The appropriate irradiation power was different for each laser apparatus and targeted cells. Thus, through this review, we tried to shed light on basic research that would ultimately lead to clinical application of periodontal phototherapy in the future.

A Polymorphism at the microRNA Binding Site in the 3' Untranslated Region of KRT81 Is Associated with Breast Cancer

Single nucleotide polymorphisms in miRNA binding sites (miR-SNPs) are associated with cancer risk. We assessed the relationship between five miR-SNPs in the 3' untranslated region (3'-UTR) of RYR3 (rs1044129), KIAA0423 (rs1053667), C14orf101 (rs4901706), GOLGA7 (rs11337), and KRT81 (rs3660) and the risk of breast cancer (BC). The CC genotype of rs3660 located in the 3'-UTR of KRT81 was identified for its association with lower BC risk (odds ratio, 0.093; 95% confidence interval, 0.045-0.193; p = 0.000). Immunnochemical analysis and Renilla luciferase reporter assays indicated that the CC genotype of KRT81 was associated with lower expression of KRT81 (p < 0.05). The subsequently functional analysis showed that knockdown the KRT81 could inhibit proliferation and promote apoptosis of the MDA-MB-231 BC cells (p < 0.05) with monocyte chemotactic protein-1 (MCP-1) deregulation. Meanwhile, KRT81 overexpression could promote the proliferation and inhibit the apoptosis of MCF-7 BC cells (p < 0.05). Our data demonstrated that the KRT81 expressional change modulated by rs3660 miR-SNP could modify the carcinogenesis of BC, thereby KRT81 would be a new target for BC treatment.

Effect of photobiomodulation on cellular migration and survival in diabetic and hypoxic diabetic wounded fibroblast cells

A disrupted wound repair process often leads to the development of chronic wounds, and pose a major physical, social and economic inconvenience on patients and the public health sector. Chronic wounds are a common complication seen in diabetes mellitus (DM), and often the severity necessitates amputation of the lower limbs. Recently, there has been increasing evidence that photobiomodulation (PBM) initiates wound healing, including increased protein transcription for cell proliferation, viability, migration and tissue reepithelialisation. Here, the hypothesis that PBM at a wavelength of 660 nm and energy density of 5 J/cm² regulates wound repair in diabetic wounded and hypoxic diabetic wounded fibroblasts by enhancing cell migration and survival was investigated. PBM increased migration and survival in diabetic wounded and hypoxic diabetic wounded fibroblasts. Our findings suggest that PBM enhances migration and survival in diabetic wounded and hypoxic diabetic wounded fibroblasts, indicating that this therapeutic method may be beneficial against chronic wounds in diabetic patients.

Photobiomodulation with 808-nm diode laser enhances gingival wound healing by promoting migration of human gingival mesenchymal stem cells via ROS/JNK/NF-κB/MMP-1 pathway

Photobiomodulation (PBM) has been shown to improve wound healing by promoting mesenchymal stem cell migration and proliferation. However, it remains unknown whether an 808-nm diode laser can influence human gingival mesenchymal stem cells (HGMSCs), and which dose this works well. In the present study, it was found that PBM could promote the migration of HGMSCs but not the proliferation. Furthermore, PBM could activate mitochondrial ROS, which could elevate the phosphorylation levels of JNK and IKB in HGMSCs, and further activate NF-κB as the nuclear translocation of p65 is elevated. Taken together, these present results indicate that PBM might promote cell migration via the ROS/JNK/NF-κB pathway.

Vaccarin Regulates Diabetic Chronic Wound Healing through FOXP2/AGGF1 Pathways

Background: Diabetes mellitus is a growing global health issue nearly across the world. Diabetic patients who are prone to develop diabetes-related complications often exhibit progressive neuropathy (painless and sensory loss). It is usual for small wounds to progress to ulceration, which especially worsens with peripheral arterial disease and in the presence of anaerobic bacteria, culminating into gangrene. In our study, vaccarin (VAC), the main active monomer extracted from Chinese herb vaccariae semen, is proven to have a role in promoting diabetic chronic wound healing through a cytoprotective role under high glucose conditions. Materials and methods: We constructed a pressure ulcer on both VAC-treated and control mice based on a type 1 diabetes (T1DM) model. The wound healing index was evaluated by an experimental wound assessment tool (EWAT). We also determined the effect of VAC on the proliferation and cell migration of human microvascular endothelial cells (HMEC-1) by a cell counting kit (CCK-8), a scratch and transwell assay. Results: The results demonstrated that VAC could promote the proliferation and migration of high glucose-stimulated HMEC-1 cells, which depend on the activation of FOXP2/AGGF1. Activation of the angiogenic factor with G patch and FHA domains 1 (AGGF1) caused enhanced phosphorylation of serine/threonine kinase (Akt) and extracellular regulated protein kinases (Erk1/2). By silencing the expression of forkhead box p2 (FOXP2) protein by siRNA, both mRNA and protein expression of AGGF1 were downregulated, leading to a decreased proliferation and migration of HMEC-1 cells. In addition, a diabetic chronic wound model in vivo unveiled that VAC had a positive effect on chronic wound healing, which involved the activation of the above-mentioned pathways. Conclusions: In summary, our study found that VAC promoted chronic wound healing in T1DM mice by activating the FOXP2/AGGF1 pathway, indicating that VAC may be a promising candidate for the treatment of the chronic wounds of diabetic patients.

Besides Photothermal Effects, Low-Level CO2 Laser Irradiation Can Potentiate Skin Microcirculation Through Photobiomodulation Mechanisms

Background: Improvement of microcirculation is one of the important mechanisms of low-level laser therapy (LLLT) to treat some diseases such as wound healing. Most previous studies have been carried out with multiple lasers other than the 10,600-nm CO₂ laser. Recently, the CO₂ laser has been used not only as a tool for excision of soft tissues but also for therapeutic applications. Objective: To study whether low-level CO₂ laser irradiation can influence microcirculation and further explore the underlying mechanisms. Methods: Seventy-milliwatt (70-mW) CO₂ lasers irradiated the forearms of 12 participants and skin blood perfusion (SkBP) was measured with a laser speckle imager. The thermal effect of irradiation was evaluated by measuring the irradiated skin in vivo and the exposed cell suspensions in vitro. Extracellular adenosine triphosphate (eATP) of the human mast cell line (HMC-1) is assessed by luciferin-luciferase assay to explore the potential mechanisms. Results: Irradiation caused dose-dependent increase in SkBP. At a medium dose of 262 J/cm², SkBP reached its maximum value at 195.8% ± 18.6% of the baseline (n = 12, p < 0.01). Such laser irradiation had a mild thermal effect, heating local skin temperature (SkT) by 6.1°C ± 0.3°C (n = 10) and warming cell suspensions by 4.5°C ± 0.8°C (n = 6). Irradiation dose-dependently lowered eATP levels of HMC-1 cells in vitro. At a medium dose of 262 J/cm², eATP levels declined to the minimum at 74.8% ± 5.5% of the baseline (n = 12, p < 0.01). This downregulation effect could be significantly inhibited by 100-μM ARL67156, a nonspecific ecto-ATPase inhibitor. On the contrary, heating itself slightly raised the level of eATP. Conclusions: Low-level CO₂ laser irradiation can improve microcirculation. Besides the thermal effect, regulation of extravascular eATP by the photobiomodulation mechanism may be involved. This implies that CO₂ lasers might be used in LLLT.

Interleukin (IL)-22 from IL-20 Subfamily of Cytokines Induces Colonic Epithelial Cell Proliferation Predominantly through ERK1/2 Pathway

The interleukin (IL)-20 subfamily of cytokines consists of IL-19, IL-20, IL-22, IL-24, and IL-26, and the expression of IL-20, IL-22, and IL-24 is reported to be higher in the colon of patients with ulcerative colitis. Although the receptors for these cytokines are highly expressed in the colon epithelium, their effects on epithelial renewal are not clearly understood. This study evaluated the effects of IL-20, IL-22, and IL-24 in epithelial renewal using the LS174T human colon cancer epithelial cell line. LS174T cells were treated with IL-20, IL-22, and IL-24 (25, 50, and 100 ng/mL) and a live-cell imaging system was used to evaluate the effects on cell proliferation. Following treatment, the signaling pathways contributing to cell proliferation were investigated through Western blotting in LS174T cells and downstream transcriptional changes through qRT-PCR in LS174T cells, and RNA-Seq in primary murine intestinal epithelial cells. Our results demonstrated that only IL-22 promoted LS174T cell proliferation, mediated via extracellular-signal-regulated kinase (ERK)1/2-mediated downstream regulation of p90RSK, c-Jun, and transcriptional changes of TRIM15 and STOM. IL-22 also promoted expression of ERK1/2-independent genes such as DDR2, LCN2, and LRG1, which are known to be involved in cell proliferation and migration. This study suggests that IL-22 induces cell proliferation in highly proliferative cells such as intestinal epithelial cells.

Effect of photobiomodulation on neural differentiation of human umbilical cord mesenchymal stem cells

Photobiomodulation therapy (PBMT) can enhance the mesenchymal stem cell (MSC) proliferation, differentiation, and tissue repair and can therefore be used in regenerative medicine. The objective of this study is to investigate the effects of photobiomodulation on the directional neural differentiation of human umbilical cord mesenchymal stem cells (hUC-MSCs) and provide a theoretical basis for neurogenesis. hUC-MSCs were divided into control, inducer, laser, and lasers combined with inducer groups. A 635-nm laser and an 808-nm laser delivering energy densities from 0 to 10 J/cm² were used in the study. Normal cerebrospinal fluid (CSF) and injured cerebrospinal fluid (iCSF) were used as inducers. The groups were continuously induced for 3 days. Cellular proliferation was evaluated using MTT. The marker proteins nestin (marker protein of the neural precursor cells), NeuN (marker protein of neuron), and GFAP (glial fibrillary acidic protein, marker proteins of glial cells) were detected by immunofluorescence and western blot. We found that irradiation with 635-nm laser increased cell proliferation, and that with 808 nm laser by itself and combined with cerebrospinal fluid treatment generated significant neuron-like morphological changes in the cells at 72 h. Nestin showed high positive expression at 24 h in the 808 nm group. The expression of GFAP increased in the 808-nm combined inducer group at 24 h but decreased at 72 h. The expression of neuN protein increased only at 72 h in both the 808-nm combined inducer group and inducer group. We concluded that 808 nm laser irradiation could help CSF to induce neuronal differentiation of hUC-MSCs in early stage and tend to change to neuron rather than glial cells.

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

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