Human Tubal-Derived Mesenchymal Stromal Cells Associated with Low Level Laser Therapy Significantly Reduces Cigarette Smoke-Induced COPD in C57BL/6 mice

Effect of photobiomodulation in the balance between effector and regulatory T cells in an experimental model of COPD

Introduction

Currently, Chronic Obstructive Pulmonary Disease (COPD) has a high impact on morbidity and mortality worldwide. The increase of CD4+, CD8+ cells expressing NF-κB, STAT4, IFN-γ and perforin are related to smoking habit, smoking history, airflow rate, obstruction and pulmonary emphysema. Furthermore, a deficiency in CD4+CD25+Foxp3+ regulatory T cells (Tregs) may impair the normal function of the immune system and lead to respiratory immune disease. On the other hand, the anti-inflammatory cytokine IL-10, produced by Treg cells and macrophages, inhibits the synthesis of several pro-inflammatory cytokines that are expressed in COPD. Therefore, immunotherapeutic strategies, such as Photobiomodulation (PBM), aim to regulate the levels of cytokines, chemokines and transcription factors in COPD. Consequently, the objective of this study was to evaluate CD4+STAT4 and CD4+CD25+Foxp3+ cells as well as the production of CD4+IFN- γ and CD4+CD25+IL-10 in the lung after PBM therapy in a COPD mice model.

Methods

We induced COPD in C57BL/6 mice through an orotracheal application of cigarette smoke extract. PMB treatment was applied for the entire 7 weeks and Bronchoalveolar lavage (BAL) and lungs were collected to study production of IFN- γ and IL-10 in the lung. After the last administration with cigarette smoke extract (end of 7 weeks), 24 h later, the animals were euthanized. One-way ANOVA followed by NewmanKeuls test were used for statistical analysis with significance levels adjusted to 5% (p < 0.05).

Results

This result showed that PBM improves COPD symptomatology, reducing the number of inflammatory cells (macrophages, neutrophils and lymphocytes), the levels of IFN-γ among others, and increased IL-10. We also observed a decrease of collagen, mucus, bronchoconstriction index, alveolar enlargement, CD4+, CD8+, CD4+STAT4+, and CD4+IFN-γ+ cells. In addition, in the treated group, we found an increase in CD4+CD25+Foxp3+ and CD4+IL-10+ T cells.

Conclusion

This study suggests that PBM treatment could be applied as an immunotherapeutic strategy for COPD.

Effects of the invasive and non-invasive systemic photobiomodulation using low-level laser in experimental models: A systematic review

Systemic photobiomodulation (PBM) of the blood or over blood vessels has been associated with bio-stimulating, vasodilating, and anti-inflammatory properties. This treatment modality has been used for modulating inflammatory processes, tissue repair, atherosclerosis, and systemic arterial hypertension, and is described more often in clinical studies than experimental models. Therefore, the aim of the present study was to conduct a literature review regarding the effect of systemic PBM involving the intravascular laser irradiation of blood (ILIB) or non-invasive vascular photobiomodulation (VPBM) using low-level laser (LLL) in experimental (animal) models. The PubMed/MEDLINE®, Scopus, SPIE Digital Library, and Web of Science databases were searched for articles on the use of VPBM with LLL in animal models. Nine original articles met the inclusion criteria and were critically evaluated. The variables of interest were the dosimetric laser parameters, different methods for delivering energy, and the main results. The use laser in the red spectrum was more prevalent and VPBM (non-invasive) predominated over ILIB (invasive). No standardization was found in the dosimetric parameters. However, the studies showed the positive effects of VPBM on arterial pressure and blood circulation, the positive effects of ILIB on blood composition and hematological markers, as well as positive effects of both forms of systemic PBM (ILIB and VPBM) on the tissue repair process. In conclusion, the studies evaluated in the present review showed that the use of systemic PBM with ILIB or non-invasive VPBM induced positive effects, modulating metabolic conditions and tissue repair. However, there is a need for standardization in the dosimetric parameters for the different conditions and processes evaluated using experimental models.

Targeting the mitochondria in chronic respiratory diseases

Mitochondria are one of the basic essential components for eukaryotic life survival. It is also the source of respiratory ATP. Recently published studies have demonstrated that mitochondria may have more roles to play aside from energy production. There is an increasing body of evidence which suggest that mitochondrial activities involved in normal and pathological states contribute to significant impact to the lung airway morphology and epithelial function in respiratory diseases such as asthma, COPD, and lung cancer. This review summarizes the pathophysiological pathways involved in asthma, COPD, lung cancer and highlights potential treatment strategies that target the malfunctioning mitochondria in such ailments. Mitochondria are responsive to environmental stimuli such as infection, tobacco smoke, and inflammation, which are essential in the pathogenesis of respiratory diseases. They may affect mitochondrial shape, protein production and ultimately cause dysfunction. The impairment of mitochondrial function has downstream impact on the cytosolic components, calcium control, response towards oxidative stress, regulation of genes and proteins and metabolic activities. Several novel compounds and alternative medicines that target mitochondria in asthma and chronic lung diseases have been discussed here. Moreover, mitochondrial enzymes or proteins that may serve as excellent therapeutic targets in COPD are also covered. The role of mitochondria in respiratory diseases is gaining much attention and mitochondria-based treatment strategies and personalized medicine targeting the mitochondria may materialize in the near future. Nevertheless, more in-depth studies are urgently needed to validate the advantages and efficacy of drugs that affect mitochondria in pathological states.

Contrasting assembly mechanisms and drivers of soil rare and abundant bacterial communities in 22-year continuous and non-continuous cropping systems

Despite many studies on the influence of cropping practices on soil microbial community structure, little is known about ecological patterns of rare and abundant microbial communities in response to different tobacco cropping systems. Here, using the high-throughput sequencing technique, we investigated the impacts of two different cropping systems on soil biochemical properties and the microbial community composition of abundant and rare taxa and its driving factors in continuous and rotational tobacco cropping systems in the mountain lands of Yunnan, China. Our results showed that distinct co-occurrence patterns and driving forces for abundant and rare taxa across the different cropping systems. The abundant taxa were mainly constrained by stochastic processes in both cropping systems. In contrast, rare taxa in continuous cropping fields were mainly influenced by environmental perturbation (cropping practice), while governed by deterministic processes under rotational cropping. The α-diversity indices of rare taxa tended to be higher than those of the abundant ones in the two cropping systems. Furthermore, the network topologies of rare taxa were more complex than those of the abundant taxa in the two cropping systems. These results highlight that rare taxa rather than abundant ones play important roles in maintaining ecosystem diversity and sustaining the stability of ecosystem functions, especially in continuous cropping systems.

Photobiomodulation Therapy Restores IL-10 Secretion in a Murine Model of Chronic Asthma: Relevance to the Population of CD4+CD25+Foxp3+ Cells in Lung

It is largely known that photobiomodulation (PBM) has beneficial effects on allergic pulmonary inflammation. Our previous study showed an anti-inflammatory effect of the PBM in an acute experimental model of asthma, and we see that this mechanism is partly dependent on IL-10. However, it remains unclear whether the activation of regulatory T cells is mediated by PBM in a chronic experimental model of asthma. In this sense, the objective of this study was to verify the anti-inflammatory role of the PBM in the pulmonary inflammatory response in a chronic experimental asthma model. The protocol used for asthma induction was the administration of OVA subcutaneously (days 0 and 14) and intranasally (3 times/week, for 5 weeks). On day 50, the animals were sacrificed for the evaluation of the different parameters. The PBM used was the diode, with a wavelength of 660 nm, a power of 100 mW, and 5 J for 50 s/point, in three different application points. Our results showed that PBM decreases macrophages, neutrophils, and lymphocytes in the bronchoalveolar lavage fluid (BALF). Moreover, PBM decreased the release of cytokines by the lung, mucus, and collagen in the airways and pulmonary mechanics. When we analyzed the percentage of Treg cells in the group irradiated with laser, we verified an increase in these cells, as well as the release of IL-10 in the BALF. Therefore, we conclude that the use of PBM therapy in chronic airway inflammation attenuated the inflammatory process, as well as the pulmonary functional and structural parameters, probably due to an increase in Treg cells.

Therapeutic Potential of Human Umbilical Cord-Derived Mesenchymal Stem Cells in Recovering From Murine Pulmonary Emphysema Under Cigarette Smoke Exposure

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) were shown to have potential for immunoregulation and tissue repair. The objective of this study was to investigate the effects of hUC-MSCs on emphysema in chronic obstructive pulmonary disease (COPD). The C57BL/6JNarl mice were exposed to cigarette smoke (CS) for 4 months followed by administration of hUC-MSCs at 3 × 10⁶ (low dose), 1 × 10⁷ (medium dose), and 3 × 10⁷ cells/kg body weight (high dose). The hUC-MSCs caused significant decreases in emphysema severity by measuring the mean linear intercept (MLI) and destructive index (DI). A decrease in neutrophils (%) and an increase in lymphocytes (%) in bronchoalveolar lavage fluid (BALF) were observed in emphysematous mice after hUC-MSC treatment. Lung levels of interleukin (IL)-1β, C-X-C motif chemokine ligand 1 (CXCL1)/keratinocyte chemoattractant (KC), and matrix metalloproteinase (MMP)-12 significantly decreased after hUC-MSC administration. Significant reductions in tumor necrosis factor (TNF)-α, IL-1β, and IL-17A in serum occurred after hUC-MSC administration. Notably, the cell viability of lung fibroblasts improved with hUC-MSCs after being treated with CS extract (CSE). Furthermore, the hUC-MSCs-conditioned medium (hUC-MSCs-CM) restored the contractile force, and increased messenger RNA expressions of elastin and fibronectin by lung fibroblasts. In conclusion, hUC-MSCs reduced inflammatory responses and emphysema severity in CS-induced emphysematous mice.

Human Fallopian Tube - Derived Mesenchymal Stem Cells Inhibit Experimental Autoimmune Encephalomyelitis by Suppressing Th1/Th17 Activation and Migration to Central Nervous System

Mesenchymal stem cells comprise a natural reservoir of undifferentiated cells within adult tissues. Given their self-renewal, multipotency, regenerative potential and immunomodulatory properties, MSCs have been reported as a promising cell therapy for the treatment of different diseases, including neurodegenerative and autoimmune diseases. In this study, we investigated the immunomodulatory properties of human tubal mesenchymal stem cells (htMSCs) using the EAE model. htMSCs were able to suppress dendritic cells activation downregulating antigen presentation-related molecules, such as MHCII, CD80 and CD86, while impairing IFN-γ and IL-17 and increasing IL-10 and IL-4 secretion. It further correlated with milder disease scores when compared to the control group due to fewer leukocytes infiltrating the CNS, specially Th1 and Th17 lymphocytes, associated with increased IL-10 secreting Tr1 cells. Conversely, microglia were less activated and infiltrating mononuclear cells secreted higher levels of IL-4 and IL-10 and expressed reduced chemokine receptors as CCR4, CCR6 and CCR8. qPCR of the spinal cords revealed upregulation of indoleamine-2,3-dioxygenase (IDO) and brain derived neurotrophic factor (BDNF). Taken together, here evidenced the potential of htMSCs as an alternative for the treatment of inflammatory, autoimmune or neurodegenerative diseases.

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

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

Impact of one versus two doses of mesenchymal stromal cells on lung and cardiovascular repair in experimental emphysema

Background

A single administration of mesenchymal stromal cells (MSCs) has been shown to reduce lung inflammation in experimental elastase-induced emphysema; however, effects were limited in terms of lung-tissue repair and cardiac function improvement. We hypothesized that two doses of MSCs could induce further lung and cardiovascular repair by mitigating inflammation and remodeling in a model of emphysema induced by multiple elastase instillations. We aimed to comparatively investigate the effects of one versus two doses of MSCs, administered 1 week apart, in a murine model of elastase-induced emphysema.

Methods

C57BL/6 mice were randomly divided into control (CTRL) and emphysema (E) groups. Mice in the E group received porcine pancreatic elastase (0.2 IU, 50 μL) intratracheally once weekly for four consecutive weeks; the CTRL animals received sterile saline (50 μL) using the same protocol. Three hours after the last instillation, the E group was further randomized to receive either saline (SAL) or murine MSCs (10⁵ cells) intratracheally, in one or two doses (1 week apart). Fourteen days later, mice were euthanized, and all data analyzed.

Results

Both one and two doses of MSCs improved lung mechanics, reducing keratinocyte-derived chemokine and transforming growth factor-β levels in lung homogenates, total cell and macrophage counts in bronchoalveolar lavage fluid (BALF), and collagen fiber content in airways and blood vessels, as well as increasing vascular endothelial growth factor in lung homogenates and elastic fiber content in lung parenchyma. However, only the two-dose group exhibited reductions in tumor necrosis factor-α in lung tissue, BALF neutrophil and lymphocyte count, thymus weight, and total cellularity, as well as CD8⁺ cell counts and cervical lymph node CD4⁺ and CD8⁺ T cell counts, as well as further increased elastic fiber content in the lung parenchyma and reduced severity of pulmonary arterial hypertension.

Conclusions

Two doses of MSCs enhanced lung repair and improvement in cardiac function, while inducing T cell immunosuppression, mainly of CD8⁺ cells, in elastase-induced emphysema.

Mesenchymal stromal cells: a novel therapy for the treatment of chronic obstructive pulmonary disease?

COPD is characterised by tissue destruction and inflammation. Given the lack of curative treatments and the progressive nature of the disease, new treatments for COPD are highly relevant. In vitro cell culture and animal studies have demonstrated that mesenchymal stromal cells (MSCs) have the capacity to modify immune responses and to enhance tissue repair. These properties of MSCs provided a rationale to investigate their potential for treatment of a variety of diseases, including COPD. Preclinical models support the hypothesis that MSCs may have clinical efficacy in COPD. However, although clinical trials have demonstrated the safety of MSC treatment, thus far they have not provided evidence for MSC efficacy in the treatment of COPD. In this review, we discuss the rationale for MSC-based cell therapy in COPD, the main findings from in vitro and in vivo preclinical COPD model studies, clinical trials in patients with COPD and directions for further research.

Can Youthful Mesenchymal Stem Cells from Wharton's Jelly Bring a Breath of Fresh Air for COPD?

Chronic obstructive pulmonary disease (COPD) is a major global cause of morbidity and mortality, projected to become the 3rd cause of disease mortality worldwide by 2020. COPD is characterized by persistent and not fully reversible airflow limitation that is usually progressive and is associated with an abnormal chronic inflammatory response of the lung to noxious agents including cigarette smoke. Currently available therapeutic strategies aim to ease COPD symptoms but cannot prevent its progress or regenerate physiological lung structure or function. The urgently needed new approaches for the treatment of COPD include stem cell therapies among which transplantation of mesenchymal stem cells derived from Wharton’s jelly (WJ-MSCs) emerges as a promising therapeutic strategy because of the unique properties of these cells. The present review discusses the main biological properties of WJ-MSCs pertinent to their potential application for the treatment of COPD in the context of COPD pathomechanisms with emphasis on chronic immune inflammatory processes that play key roles in the development and progression of COPD.

Effects of periodontitis on the development of asthma: The role of photodynamic therapy

To evaluate whether periodontitis modulates lung inflammation in an experimental model of asthma as well as the photodynamic therapy (PDT) is associated with a reduction of lung inflammation. Seventy-two BALB/c male mice (~2 months) were randomly divided into 8 groups (n = 9): Basal, Periodontitis (P), P+PT, P+PT+PDT, Asthma (A), A+P, A+P+PT, and A+P+PT+PDT. Periodontitis was induced by using the ligature technique and asthma was induced by ovalbumin (OVA). PT was performed with curettes and PDT with methylene blue (0.005%), λ = 660nm, with a radiant exposure of 318J/cm². After 43 days, euthanasia was carried out prior to lung and mandible morphological analyzes. All of the manipulations of the animals were performed by only one operator. The total and differential cell counts and cytokines IL-4, IL-5, IL-10, IFN-γ, TNF-α, IL-1β, and IL-6 were evaluated in the bronchoalveolar lavage (BAL) and in the serum. Mucus and alkaline phosphatase were also quantified. Statistical analyzes were performed by a blinded statistician. One-way analysis of variance (ANOVA) was employed, followed by the Student-Newman-Keuls test. Periodontitis group (P) increased alkaline phosphatase and bone resorption (p<0.05), validating the experimental model of periodontitis. The A group and the P group increased the total amount of cells (p <0.05) in the BAL. However, in the A+P group, there was a decrease in these cells, except for in the A+P+PT+PDT group (p<0.05). The asthma group increased the Th2 cytokines and P group increased the Th1 cytokine profile, and A+P+PT+PDT group increased IL-10 cytokine. Mucus was increased for the A and P groups. In conclusion, periodontitis in the asthmatic mice reduced the inflammatory migrated cells in the BAL (eosinophils, lymphocytes, macrophages). In addition, it reduced the levels of the IL-4 and TNF-α cytokines, which was also accompanied by a decreased mucus production. After PDT treatment the total cell count increased however, this increase was not accompanied by a pro-inflammatory cytokines release. Only in PDT group the anti-inflammatory IL-10 was increased. Further studies are needed to understand this mechanism of action.

Mesenchymal stromal cell therapy in COPD: from bench to bedside

COPD is the most frequent chronic respiratory disease and a leading cause of morbidity and mortality. The major risk factor for COPD development is cigarette smoke, and the most efficient treatment for COPD is smoking cessation. However, even after smoking cessation, inflammation, apoptosis, and oxidative stress may persist and continue contributing to disease progression. Although current therapies for COPD (primarily based on anti-inflammatory agents) contribute to the reduction of airway obstruction and minimize COPD exacerbations, none can avoid disease progression or reduce mortality. Within this context, recent advances in mesenchymal stromal cell (MSC) therapy have made this approach a strong candidate for clinical use in the treatment of several pulmonary diseases. MSCs can be readily harvested from diverse tissues and expanded with high efficiency, and have strong immunosuppressive properties. Preclinical studies have demonstrated encouraging outcomes of MSCs therapy for lung disorders, including emphysema. These findings instigated research groups to assess the impact of MSCs in human COPD/emphysema, but clinical results have fallen short of expectations. However, MSCs have demonstrated a good adjuvant role in the clinical scenario. Trials that used MSCs combined with another, primary treatment (eg, endobronchial valves) found that patients derived greater benefit in pulmonary function tests and/or quality of life reports, as well as reductions in systemic markers of inflammation. The present review summarizes and describes the more recent preclinical studies that have been published about MSC therapy for COPD/emphysema and discusses what has already been applied about MSCs treatment in COPD patients in the clinical setting.

Immunomodulatory effects of two different physical therapy modalities in patients with chronic obstructive pulmonary disease

[Purpose] Counteracting the systemic cytokine release and its inflammatory effects by improving respiratory muscle strength and controlling lung inflammation may be important for improving immune system in patients with chronic obstructive pulmonary disease, So the aim of the present study was to evaluate the effect of low level laser therapy and inspiratory muscle training on interleukin-6 (IL-6) as a marker of inflammation and CD4+/CD8+ ratio as a marker for T Lymphocytes in these patients. [Subjects and Methods] Forty male patients with stable COPD participated in the study, their ages ranged between 55−65 years. They were randomly divided into group (A) who received inspiratory muscle training and group (B) who received low level laser (LLL) acupuncture stimulation for about 8 week. [Results] There was a reduction in the concentration of plasma IL-6 associated with an increase in CD4+/CD8+ ratio in both groups, but laser was superior to inspiratory muscle training. IL-6 and CD4+/CD8+ were negatively correlated. [Conclusion] Both inspiratory muscle training and low level laser therapy are effective physical therapy modalities in promoting immune disturbances. The results also supported the superior role of LLLT over IMT in managing immune disturbances.

Photobiomodulation therapy improves both inflammatory and fibrotic parameters in experimental model of lung fibrosis in mice

Lung fibrosis (LF) is a chronic and progressive lung disease characterized by pulmonary parenchyma progressive lesion, inflammatory infiltration, and interstitial fibrosis. It is developed by excessive collagen deposition and other cellular matrix components, resulting in severe changes in the alveolar architecture. Considering the absence of effective treatment, the aim of this study was to investigate the effect of photobiomodulation therapy (PBMT) on the development of PF. For this purpose, we used C57BL6 mice subjected to induction of LF by bleomycin administration (1.5 U/kg) by orotracheal route and, after 14 days of the induction, mice were treated with PBMT applied to the thorax 1×/day for 8 days (wavelength 660 ± 20 nm, power 100 mW, radiant exposure 5 J/cm², irradiance 33.3 mW/cm², spot size 2.8cm², total energy 15 J, time of irradiation: 150 s) and inflammatory and fibrotic parameters were evaluated with or without PBMT. Our results showed that PBMT significantly reduced the number of inflammatory cells in the alveolar space, collagen production, interstitial thickening, and static and dynamic pulmonary elastance. In addition, we observed reduced levels of IL-6 e CXCL1/KC released by pneumocytes in culture as well as reduced level of CXCL1/KC released by fibroblasts in culture. We can conclude that the PBMT improves both inflammatory and fibrotic parameters showing a promising therapy which is economical and has no side effects.

Human mesenchymal stromal cells exert HGF dependent cytoprotective effects in a human relevant pre-clinical model of COPD

Bone-marrow derived mesenchymal stromal cells (MSCs) have potent immunomodulatory and tissue reparative properties, which may be beneficial in the treatment of inflammatory diseases such as COPD. This study examined the mechanisms by which human MSCs protect against elastase induced emphysema. Using a novel human relevant pre-clinical model of emphysema the efficacy of human MSC therapy and optimal cell dose were investigated. Protective effects were examined in the lung through histological examination. Further in vivo experiments examined the reparative abilities of MSCs after tissue damage was established and the role played by soluble factors secreted by MSCs. The mechanism of MSC action was determined in using shRNA gene knockdown. Human MSC therapy and MSC conditioned media exerted significant cytoprotective effects when administered early at the onset of the disease. These protective effects were due to significant anti-inflammatory, anti-fibrotic and anti-apoptotic mechanisms, mediated in part through MSC production of hepatocyte growth factor (HGF). When MSC administration was delayed, significant protection of the lung architecture was observed but this was less extensive. MSC cell therapy was more effective than MSC conditioned medium in this emphysema model.

Preclinical Studies of Mesenchymal Stem Cell (MSC) Administration in Chronic Obstructive Pulmonary Disease (COPD): A Systematic Review and Meta-Analysis

BACKGROUND

In the last two decades, mesenchymal stem cells (MSCs) have been pre-clinically utilized in the treatment of a variety of kinds of diseases including chronic obstructive pulmonary disease (COPD). The aim of the current study was to systematically review and conduct a meta-analysis on the published pre-clinical studies of MSC administration in the treatment of COPD in animal models.

METHODS AND RESULTS

A systematic search of electronic databases was performed. Statistical analysis was performed using the Comprehensive Meta-Analysis software (Version 3). The pooled Hedges's g with 95% confidence intervals (95% CIs) was adopted to assess the effect size. Random effect model was used due to the heterogeneity between the studies. A total of 20 eligible studies were included in the current systematic review. The overall meta-analysis showed that MSC administration was significantly in favor of attenuating acute lung injury (Hedges's g = -2.325 ± 0.145 with 95% CI: -2.609 ~ -2.040, P < 0.001 for mean linear intercept, MLI; Hedges's g = -3.488 ± 0.504 with 95% CI: -4.476 ~ -2.501, P < 0.001 for TUNEL staining), stimulating lung tissue repair (Hedges's g = 3.249 ± 0.586 with 95% CI: 2.103~ 4.394, P < 0.001) and improving lung function (Hedges's g = 2.053 ± 0.408 with 95% CI: 1.253 ~ 2.854, P< 0.001). The mechanism of MSC therapy in COPD is through ameliorating airway inflammation (Hedges's g = -2.956 ± 0.371 with 95% CI: -3.683 ~ -2.229, P< 0.001) and stimulating cytokine synthesis that involves lung tissue repair (Hedges's g = 3.103 ± 0.734 with 95% CI: 1.664 ~ 4.541, P< 0.001).

CONCLUSION

This systematic review and meta-analysis suggest a promising role for MSCs in COPD treatment. Although the COPD models may not truly mimic COPD patients, these pre-clinical studies demonstrate that MSC hold promise in the treatment of chronic lung diseases including COPD. The mechanisms of MSCs role in preclinical COPD treatment may be associated with attenuating airway inflammation as well as stimulating lung tissue repair.

Photobiomodulation Therapy Decreases Oxidative Stress in the Lung Tissue after Formaldehyde Exposure: Role of Oxidant/Antioxidant Enzymes

Formaldehyde is ubiquitous pollutant that induces oxidative stress in the lung. Several lung diseases have been associated with oxidative stress and their control is necessary. Photobiomodulation therapy (PBMT) has been highlighted as a promissory treatment, but its mechanisms need to be better investigated. Our objective was to evaluate the effects of PBMT on the oxidative stress generated by FA exposure. Male Wistar rats were submitted to FA exposure of 1% or vehicle (3 days) and treated or not with PBMT (1 and 5 h after each FA exposure). Rats treated only with laser were used as control. Twenty-four hours after the last FA exposure, we analyzed the effects of PBMT on the generation of nitrites and hydrogen peroxide, oxidative burst, glutathione reductase, peroxidase, S-transferase enzyme activities, the gene expression of nitric oxide, cyclooxygenase, superoxide dismutase, the catalase enzyme, and heme oxygenase-1. PBMT reduced the generation of nitrites and hydrogen peroxide and increased oxidative burst in the lung cells. A decreased level of oxidant enzymes was observed which were concomitantly related to an increased level of antioxidants. This study provides new information about the antioxidant mechanisms of PBMT in the lung and might constitute an important tool for lung disease treatment.

Low Level Laser Therapy Reduces the Development of Lung Inflammation Induced by Formaldehyde Exposure

Lung diseases constitute an important public health problem and its growing level of concern has led to efforts for the development of new therapies, particularly for the control of lung inflammation. Low Level Laser Therapy (LLLT) has been highlighted as a non-invasive therapy with few side effects, but its mechanisms need to be better understood and explored. Considering that pollution causes several harmful effects on human health, including lung inflammation, in this study, we have used formaldehyde (FA), an environmental and occupational pollutant, for the induction of neutrophilic lung inflammation. Our objective was to investigate the local and systemic effects of LLLT after FA exposure. Male Wistar rats were exposed to FA (1%) or vehicle (distillated water) during 3 consecutive days and treated or not with LLLT (1 and 5 hours after each FA exposure). Non-manipulated rats were used as control. 24 h after the last FA exposure, we analyzed the local and systemic effects of LLLT. The treatment with LLLT reduced the development of neutrophilic lung inflammation induced by FA, as observed by the reduced number of leukocytes, mast cells degranulated, and a decreased myeloperoxidase activity in the lung. Moreover, LLLT also reduced the microvascular lung permeability in the parenchyma and the intrapulmonary bronchi. Alterations on the profile of inflammatory cytokines were evidenced by the reduced levels of IL-6 and TNF-α and the elevated levels of IL-10 in the lung. Together, our results showed that LLLT abolishes FA-induced neutrophilic lung inflammation by a reduction of the inflammatory cytokines and mast cell degranulation. This study may provide important information about the mechanisms of LLLT in lung inflammation induced by a pollutant.