Human mesenchymal stromal cells inhibit Mycobacterium avium replication in clinically relevant models of lung infection.

INTRODUCTION: Novel therapeutic strategies are urgently needed for Mycobacterium avium complex pulmonary disease (MAC-PD). Human mesenchymal stromal cells (MSCs) can directly inhibit MAC growth, but their effect on intracellular bacilli is unknown. We investigated the ability of human MSCs to reduce bacterial replication and inflammation in MAC-infected macrophages and in a murine model of MAC-PD. METHODS: Human monocyte-derived macrophages (MDMs) were infected with M. avium Chester strain and treated with human bone marrow-derived MSCs. Intracellular and extracellular colony-forming units (CFUs) were counted at 72 hours. Six-week-old female balb/c mice were infected by nebulisation of M. avium Chester. Mice were treated with 1×106 intravenous human MSCs or saline control at 21 and 28 days post-infection. Lungs, liver and spleen were harvested 42 days post-infection for bacterial counts. Cytokines were quantified by ELISA. RESULTS: MSCs reduced intracellular bacteria in MDMs over 72 hours (median 35% reduction, p=0.027). MSC treatment increased extracellular concentrations of prostaglandin E2 (PGE2) (median 10.1-fold rise, p=0.002) and reduced tumour necrosis factor-α (median 28% reduction, p=0.025). Blocking MSC PGE2 production by cyclo-oxygenase-2 (COX-2) inhibition with celecoxib abrogated the antimicrobial effect, while this was restored by adding exogenous PGE2. MSC-treated mice had lower pulmonary CFUs (median 18% reduction, p=0.012), but no significant change in spleen or liver CFUs compared with controls. CONCLUSION: MSCs can modulate inflammation and reduce intracellular M. avium growth in human macrophages via COX-2/PGE2 signalling and inhibit pulmonary bacterial replication in a murine model of chronic MAC-PD.

GMP-compliant extracellular vesicles derived from umbilical cord mesenchymal stromal cells: manufacturing and pre-clinical evaluation in ARDS treatment.

BACKGROUND AIMS: Extracellular vesicles (EVs) represent a new axis of intercellular communication that can be harnessed for therapeutic purposes, as cell-free therapies. The clinical application of mesenchymal stromal cell (MSC)-derived EVs, however, is still in its infancy and faces many challenges. The heterogeneity inherent to MSCs, differences among donors, tissue sources, and variations in manufacturing conditions may influence the release of EVs and their cargo, thus potentially affecting the quality and consistency of the final product. We investigated the influence of cell culture and conditioned medium harvesting conditions on the physicochemical and proteomic profile of human umbilical cord MSC-derived EVs (hUCMSC-EVs) produced under current good manufacturing practice (cGMP) standards. We also evaluated the efficiency of the protocol in terms of yield, purity, productivity, and expression of surface markers, and assessed the biodistribution, toxicity and potential efficacy of hUCMSC-EVs in pre-clinical studies using the LPS-induced acute lung injury model. METHODS: hUCMSCs were isolated from a cord tissue, cultured, cryopreserved, and characterized at a cGMP facility. The conditioned medium was harvested at 24, 48, and 72 h after the addition of EV collection medium. Three conventional methods (nanoparticle tracking analysis, transmission electron microscopy, and nanoflow cytometry) and mass spectrometry were used to characterize hUCMSC-EVs. Safety (toxicity of single and repeated doses) and biodistribution were evaluated in naive mice after intravenous administration of the product. Efficacy was evaluated in an LPS-induced acute lung injury model. RESULTS: hUCMSC-EVs were successfully isolated using a cGMP-compliant protocol. Comparison of hUCMSC-EVs purified from multiple harvests revealed progressive EV productivity and slight changes in the proteomic profile, presenting higher homogeneity at later timepoints of conditioned medium harvesting. Pooled hUCMSC-EVs showed a non-toxic profile after single and repeated intravenous administration to naive mice. Biodistribution studies demonstrated a major concentration in liver, spleen and lungs. HUCMSC-EVs reduced lung damage and inflammation in a model of LPS-induced acute lung injury. CONCLUSIONS: hUCMSC-EVs were successfully obtained following a cGMP-compliant protocol, with consistent characteristics and pre-clinical safety profile, supporting their future clinical development as cell-free therapies.

Acetylsalicylic acid and dihydroartemisinin combined therapy on experimental malaria-associated acute lung injury: analysis of lung function and the inflammatory process.

BACKGROUND: Severe malaria can cause respiratory symptoms, which may lead to malaria-acute lung injury (MA-ALI) due to inflammation and damage to the blood-gas barrier. Patients with severe malaria also often present thrombocytopenia, and the use of acetylsalicylic acid (ASA), a commonly used non-steroidal anti-inflammatory drug with immunomodulatory and antiplatelet effects, may pose a risk in regions where malaria is endemic. Thus, this study aimed to investigate the systemic impact of ASA and dihydroartemisinin (DHA) on ALI induced in mice by Plasmodium berghei NK65 (PbNK65). METHODS: C57BL/6 mice were randomly divided into control (C) and PbNK65 infected groups and were inoculated with uninfected or 104 infected erythrocytes, respectively. Then, the animals were treated with DHA (3 mg/kg) or vehicle (DMSO) at the 8-day post-infection (dpi) for 7 days and with ASA (100 mg/kg, single dose), and analyses were performed at 9 or 15 dpi. Lung mechanics were performed, and lungs were collected for oedema evaluation and histological analyses. RESULTS: PbNK65 infection led to lung oedema, as well as increased lung static elastance (Est, L), resistive (ΔP1, L) and viscoelastic (ΔP2, L) pressures, percentage of mononuclear cells, inflammatory infiltrate, hemorrhage, alveolar oedema, and alveolar thickening septum at 9 dpi. Mice that received DHA or DHA + ASA had an increase in Est, L, and CD36 expression on inflammatory monocytes and higher protein content on bronchoalveolar fluid (BALF). However, only the DHA-treated group presented a percentage of inflammatory monocytes similar to the control group and a decrease in ΔP1, L and ΔP2, L compared to Pb + DMSO. Also, combined treatment with DHA + ASA led to an impairment in diffuse alveolar damage score and lung function at 9 dpi. CONCLUSIONS: Therapy with ASA maintained lung morpho-functional impairment triggered by PbNK65 infection, leading to a large influx of inflammatory monocytes to the lung tissue. Based on its deleterious effects in experimental MA-ALI, ASA administration or its treatment maintenance might be carefully reconsidered and further investigated in human malaria cases.

Mesenchymal stromal cells-derived extracellular vesicles reprogramme macrophages in ARDS models through the miR-181a-5p-PTEN-pSTAT5-SOCS1 axis.

RATIONALE: A better understanding of the mechanism of action of mesenchymal stromal cells (MSCs) and their extracellular vesicles (EVs) is needed to support their use as novel therapies for acute respiratory distress syndrome (ARDS). Macrophages are important mediators of ARDS inflammatory response. Suppressor of cytokine signalling (SOCS) proteins are key regulators of the macrophage phenotype switch. We therefore investigated whether SOCS proteins are involved in mediation of the MSC effect on human macrophage reprogramming. METHODS: Human monocyte-derived macrophages (MDMs) were stimulated with lipopolysaccharide (LPS) or plasma samples from patients with ARDS (these samples were previously classified into hypo-inflammatory and hyper-inflammatory phenotype) and treated with MSC conditioned medium (CM) or EVs. Protein expression was measured by Western blot. EV micro RNA (miRNA) content was determined by miRNA sequencing. In vivo: LPS-injured C57BL/6 mice were given EVs isolated from MSCs in which miR-181a had been silenced by miRNA inhibitor or overexpressed using miRNA mimic. RESULTS: EVs were the key component of MSC CM responsible for anti-inflammatory modulation of human macrophages. EVs significantly reduced secretion of tumour necrosis factor-α and interleukin-8 by LPS-stimulated or ARDS plasma-stimulated MDMs and this was dependent on SOCS1. Transfer of miR-181a in EVs downregulated phosphatase and tensin homolog (PTEN) and subsequently activated phosphorylated signal transducer and activator of transcription 5 (pSTAT5) leading to upregulation of SOCS1 in macrophages. In vivo, EVs alleviated lung injury and upregulated pSTAT5 and SOCS1 expression in alveolar macrophages in a miR181-dependent manner. Overexpression of miR-181a in MSCs significantly enhanced therapeutic efficacy of EVs in this model. CONCLUSION: miR-181a-PTEN-pSTAT5-SOCS1 axis is a novel pathway responsible for immunomodulatory effect of MSC EVs in ARDS.

Ghrelin therapy improves lung and cardiovascular function in experimental emphysema.

BACKGROUND: Emphysema is a progressive disease characterized by irreversible airspace enlargement followed by a decline in lung function. It also causes extrapulmonary effects, such as loss of body mass and cor pulmonale, which are associated with shorter survival and worse clinical outcomes. Ghrelin, a growth-hormone secretagogue, stimulates muscle anabolism, has anti-inflammatory effects, promotes vasodilation, and improves cardiac performance. Therefore, we hypothesized that ghrelin might reduce lung inflammation and remodelling as well as improve lung mechanics and cardiac function in experimental emphysema. METHODS: Forty female C57BL/6 mice were randomly assigned into two main groups: control (C) and emphysema (ELA). In the ELA group (n=20), animals received four intratracheal instillations of pancreatic porcine elastase (PPE) at 1-week intervals. C animals (n=20) received saline alone (50 µL) using the same protocol. Two weeks after the last instillation of saline or PPE, C and ELA animals received ghrelin or saline (n=10/group) intraperitoneally (i.p.) daily, during 3 weeks. Dual-energy X-ray absorptiometry (DEXA), echocardiography, lung mechanics, histology, and molecular biology were analysed. RESULTS: In elastase-induced emphysema, ghrelin treatment decreased alveolar hyperinflation and mean linear intercept, neutrophil infiltration, and collagen fibre content in the alveolar septa and pulmonary vessel wall; increased elastic fibre content; reduced M1-macrophage populations and increased M2 polarization; decreased levels of keratinocyte-derived chemokine (KC, a mouse analogue of interleukin-8), tumour necrosis factor-α, and transforming growth factor-ß, but increased interleukin-10 in lung tissue; augmented static lung elastance; reduced arterial pulmonary hypertension and right ventricular hypertrophy on echocardiography; and increased lean mass. CONCLUSION: In the elastase-induced emphysema model used herein, ghrelin not only reduced lung damage but also improved cardiac function and increased lean mass. These findings should prompt further studies to evaluate ghrelin as a potential therapy for emphysema.

Respiratory and Systemic Effects of LASSBio596 Plus Surfactant in Experimental Acute Respiratory Distress Syndrome.

BACKGROUND/AIMS: Exogenous surfactant has been proposed as adjunctive therapy for acute respiratory distress syndrome (ARDS), but it is inactivated by different factors present in the alveolar space. We hypothesized that co-administration of LASSBio596, a molecule with significant anti-inflammatory properties, and exogenous surfactant could reduce lung inflammation, thus enabling the surfactant to reduce edema and improve lung function, in experimental ARDS. METHODS: ARDS was induced by cecal ligation and puncture surgery in BALB/c mice. A sham-operated group was used as control (CTRL). After surgery (6 hours), CTRL and ARDS animals were assigned to receive: (1) sterile saline solution; (2) LASSBio596; (3) exogenous surfactant or (4) LASSBio596 plus exogenous surfactant (n = 22/group). RESULTS: Regardless of exogenous surfactant administration, LASSBio596 improved survival rate and reduced collagen fiber content, total number of cells and neutrophils in PLF and blood, cell apoptosis, protein content in BALF, and urea and creatinine levels. LASSBio596 plus surfactant yielded all of the aforementioned beneficial effects, as well as increased BALF lipid content and reduced surface tension. CONCLUSION: LASSBio596 exhibited major anti-inflammatory and anti-fibrogenic effects in experimental sepsis-induced ARDS. Its association with surfactant may provide further advantages, potentially by reducing surface tension.

The biological effects of higher and lower positive end-expiratory pressure in pulmonary and extrapulmonary acute lung injury with intra-abdominal hypertension.

INTRODUCTION: Mechanical ventilation with high positive end-expiratory pressure (PEEP) has been used in patients with acute respiratory distress syndrome (ARDS) and intra-abdominal hypertension (IAH), but the role of PEEP in minimizing lung injury remains controversial. We hypothesized that in the presence of acute lung injury (ALI) with IAH: 1) higher PEEP levels improve pulmonary morphofunction and minimize lung injury; and 2) the biological effects of higher PEEP are more effective in extrapulmonary (exp) than pulmonary (p) ALI. METHODS: In 48 adult male Wistar rats, ALIp and ALIexp were induced by Escherichia coli lipopolysaccharide intratracheally and intraperitoneally, respectively. After 24 hours, animals were anesthetized and mechanically ventilated (tidal volume of 6 mL/kg). IAH (15 mmHg) was induced and rats randomly assigned to PEEP of 5 (PEEP5), 7 (PEEP7) or 10 (PEEP10) cmH2O for 1 hour. RESULTS: In both ALIp and ALIexp, higher PEEP levels improved oxygenation. PEEP10 increased alveolar hyperinflation and epithelial cell damage compared to PEEP5, independent of ALI etiology. In ALIp, PEEP7 and PEEP10 increased lung elastance compared to PEEP5 (4.3 ± 0.7 and 4.3 ± 0.9 versus 3.1 ± 0.3 cmH2O/mL, respectively, P <0.01), without changes in alveolar collapse, interleukin-6, caspase-3, type III procollagen, receptor for advanced glycation end-products, and vascular cell adhesion molecule-1 expressions. Moreover, PEEP10 increased diaphragmatic injury compared to PEEP5. In ALIexp, PEEP7 decreased lung elastance and alveolar collapse compared to PEEP5 (2.3 ± 0.5 versus 3.6 ± 0.7 cmH2O/mL, P <0.02, and 27.2 (24.7 to 36.8) versus 44.2 (39.7 to 56.9)%, P <0.05, respectively), while PEEP7 and PEEP10 increased interleukin-6 and type III procollagen expressions, as well as type II epithelial cell damage compared to PEEP5. CONCLUSIONS: In the current models of ALI with IAH, in contrast to our primary hypothesis, higher PEEP is more effective in ALIp than ALIexp as demonstrated by the activation of biological markers. Therefore, higher PEEP should be used cautiously in the presence of IAH and ALI, mainly in ALIexp.

Therapeutic effects of hypoxia-preconditioned bone marrow-derived mesenchymal stromal cells and their extracellular vesicles in experimental pulmonary arterial hypertension.

AIMS: To evaluate BM-MSCs and their extracellular vesicles (EVs) preconditioned with hypoxia or normoxia in experimental pulmonary arterial hypertension (PAH). MAIN METHODS: BM-MSCs were isolated and cultured under normoxia (MSC-N, 21%O2) or hypoxia (MSC-H, 1%O2) for 48 h. EVs were then isolated from MSCs under normoxia (EV-N) or hypoxia (EV-H). PAH was induced in male Wistar rats (n = 35) with monocrotaline (60 mg/kg); control animals (CTRL, n = 7) were treated with saline. On day 14, PAH animals received MSCs or EVs under normoxia or hypoxia, intravenously (n = 7/group). On day 28, right ventricular systolic pressure (RVSP), pulmonary acceleration time (PAT)/pulmonary ejection time (PET), and right ventricular hypertrophy (RVH) index were evaluated. Perivascular collagen content, vascular wall thickness, and endothelium-mesenchymal transition were analyzed. KEY FINDINGS: PAT/PET was lower in the PAH group (0.26 ± 0.02, P < 0.001) than in CTRLs (0.43 ± 0.02) and only increased in the EV-H group (0.33 ± 0.03, P = 0.014). MSC-N (32 ± 6 mmHg, P = 0.036), MSC-H (31 ± 3 mmHg, P = 0.019), EV-N (27 ± 4 mmHg, P < 0.001), and EV-H (26 ± 5 mmHg, P < 0.001) reduced RVSP compared with the PAH group (39 ± 4 mmHg). RVH was higher in the PAH group than in CTRL and reduced after all therapies. All therapies decreased perivascular collagen fiber content, vascular wall thickness, and the expression of endothelial markers remained unaltered; only MSC-H and EV-H decreased expression of mesenchymal markers in pulmonary arterioles. SIGNIFICANCE: MSCs and EVs, under normoxia or hypoxia, reduced right ventricular hypertrophy, perivascular collagen, and vessel wall thickness. Under hypoxia, MSCs and EVs were more effective at improving endothelial to mesenchymal transition in experimental PAH.

Investigation of the MSC Paracrine Effects on Alveolar-Capillary Barrier Integrity in the In Vitro Models of ARDS.

Acute Respiratory Distress Syndrome (ARDS) is a devastating clinical disorder with high mortality rates and no specific pharmacological treatment available yet. It is characterized by excessive inflammation in the alveolar compartment resulting in edema of the airspaces due to loss of integrity in the alveolar epithelial-endothelial barrier leading to the development of hypoxemia and often severe respiratory failure. Changes in the permeability of the alveolar epithelial-endothelial barrier contribute to excessive inflammation, the formation of lung edema and impairment of the alveolar fluid clearance. In recent years, Mesenchymal Stromal Cells (MSCs) have attracted attention as a cell therapy for ARDS. MSCs are known to secrete a variety of biologically active factors (growth factors, cytokines, and extracellular vesicles). These paracrine factors have been shown to be major effectors of the anti-inflammatory and regenerative properties observed in multiple in vitro and in vivo studies. This chapter provides a simple protocol on how to investigate the paracrine effect of MSCs on the alveolar epithelial-endothelial barrier functions.

Sepsis Disrupts Mitochondrial Function and Diaphragm Morphology.

BACKGROUND: The diaphragm is the primary muscle of inspiration, and its dysfunction is frequent during sepsis. However, the mechanisms associated with sepsis and diaphragm dysfunction are not well understood. In this study, we evaluated the morphophysiological changes of the mitochondrial diaphragm 5 days after sepsis induction. METHODS: Male C57Bl/6 mice were divided into two groups, namely, cecal ligation and puncture (CLP, n = 26) and sham-operated (n = 19). Mice received antibiotic treatment 8 h after surgery and then every 24 h until 5 days after surgery when mice were euthanized and the diaphragms were collected. Also, diaphragm function was evaluated in vivo by ultrasound 120 h after CLP. The tissue fiber profile was evaluated by the expression of myosin heavy chain and SERCA gene by qPCR and myosin protein by using Western blot. The Myod1 and Myog expressions were evaluated by using qPCR. Diaphragm ultrastructure was assessed by electron microscopy, and mitochondrial physiology was investigated by high-resolution respirometry, Western blot, and qPCR. RESULTS: Cecal ligation and puncture mice developed moderated sepsis, with a 74% survivor rate at 120 h. The diaphragm mass did not change in CLP mice compared with control, but we observed sarcomeric disorganization and increased muscle thickness (38%) during inspiration and expiration (21%). Septic diaphragm showed a reduction in fiber myosin type I and IIb mRNA expression by 50% but an increase in MyHC I and IIb protein levels compared with the sham mice. Total and healthy mitochondria were reduced by 30% in septic mice, which may be associated with a 50% decrease in Ppargc1a (encoding PGC1a) and Opa1 (mitochondria fusion marker) expressions in the septic diaphragm. The small and non-functional OPA1 isoform also increased 70% in the septic diaphragm. These data suggest an imbalance in mitochondrial function. In fact, we observed downregulation of all respiratory chain complexes mRNA expression, decreased complex III and IV protein levels, and reduced oxygen consumption associated with ADP phosphorylation (36%) in CLP mice. Additionally, the septic diaphragm increased proton leak and downregulated Sod2 by 70%. CONCLUSION: The current model of sepsis induced diaphragm morphological changes, increased mitochondrial damage, and induced functional impairment. Thus, diaphragm damage during sepsis seems to be associated with mitochondrial dysfunction.

Early Career Members at the ERS Lung Science Conference 2020: metabolic alterations in lung ageing and disease.

The Lung Science Conference 2020 brought together leading experts in the field to discuss the latest cutting-edge science, as well as various career development opportunities for early career members https://bit.ly/2XZ5YGQ.

Combined therapy with adipose tissue-derived mesenchymal stromal cells and meglumine antimoniate controls lesion development and parasite load in murine cutaneous leishmaniasis caused by Leishmania amazonensis.

BACKGROUND: Leishmaniasis is a neglected disease caused by Leishmania spp. One of its characteristics is an imbalance of host immune responses to foster parasite survival. In this setting, mesenchymal stromal cells (MSCs) may be a viable therapeutic alternative, given their well-established immunomodulatory potential. In this study, we compared the effects of therapy with bone marrow (BM)- and adipose tissue (AD)-derived MSCs in leishmaniasis caused by Leishmania amazonensis in C57BL/6 mice. After determining the most effective MSC source, we then combined these cells with meglumine antimoniate (a pentavalent antimonial commonly used for the treatment of leishmaniasis) to treat the infected mice. METHODS: In vitro, co-culture of AD-MSCs and BM-MSCs with Leishmania amazonensis-infected macrophages was performed to understand the influence of both MSC sources in infected cells. In vivo, infected C57BL/6 mice were treated with phosphate-buffered saline (PBS), AD-MSCs and BM-MSCs, and then meglumine antimoniate was combined with MSCs from the most effective source. RESULTS: In vitro, co-culture of Leishmania amazonensis-infected macrophages with BM-MSCs, compared to AD-MSCs, led to a higher parasite load and lower production of nitric oxide. Fibroblasts grown in conditioned medium from co-cultures with AD-MSCs promoted faster wound healing. Despite a non-significant difference in the production of vascular endothelial growth factor, we observed higher production of tumor necrosis factor-α and interleukin (IL)-10 in the co-culture with AD-MSCs. In vivo, treatment of infected mice with BM-MSCs did not lead to disease control; however, the use of AD-MSCs was associated with partial control of lesion development, without significant differences in the parasite load. AD-MSCs combined with meglumine antimoniate reduced lesion size and parasite load when compared to PBS and AD-MSC groups. At the infection site, we detected a small production of IL-10, but we were unable to detect production of either IL-4 or interferon-γ, indicating resolution of infection without effect on the percentage of regulatory T cells. CONCLUSION: Combination treatment of cutaneous leishmaniasis with AD-MSCs and meglumine antimoniate may be a viable alternative.

Endotoxin-Induced Emphysema Exacerbation: A Novel Model of Chronic Obstructive Pulmonary Disease Exacerbations Causing Cardiopulmonary Impairment and Diaphragm Dysfunction.

Chronic obstructive pulmonary disease (COPD) is a progressive disorder of the lung parenchyma which also involves extrapulmonary manifestations, such as cardiovascular impairment, diaphragm dysfunction, and frequent exacerbations. The development of animal models is important to elucidate the pathophysiology of COPD exacerbations and enable analysis of possible therapeutic approaches. We aimed to characterize a model of acute emphysema exacerbation and evaluate its consequences on the lung, heart, and diaphragm. Twenty-four Wistar rats were randomly assigned into one of two groups: control (C) or emphysema (ELA). In ELA group, animals received four intratracheal instillations of pancreatic porcine elastase (PPE) at 1-week intervals. The C group received saline under the same protocol. Five weeks after the last instillation, C and ELA animals received saline (SAL) or E. coli lipopolysaccharide (LPS) (200 µg in 200 µl) intratracheally. Twenty-four hours after saline or endotoxin administration, arterial blood gases, lung inflammation and morphometry, collagen fiber content, and lung mechanics were analyzed. Echocardiography, diaphragm ultrasonography (US), and computed tomography (CT) of the chest were done. ELA-LPS animals, compared to ELA-SAL, exhibited decreased arterial oxygenation; increases in alveolar collapse (p < 0.0001), relative neutrophil counts (p = 0.007), levels of cytokine-induced neutrophil chemoattractant-1, interleukin (IL)-1ß, tumor necrosis factor-α, IL-6, and vascular endothelial growth factor in lung tissue, collagen fiber deposition in alveolar septa, airways, and pulmonary vessel walls, and dynamic lung elastance (p < 0.0001); reduced pulmonary acceleration time/ejection time ratio, (an indirect index of pulmonary arterial hypertension); decreased diaphragm thickening fraction and excursion; and areas of emphysema associated with heterogeneous alveolar opacities on chest CT. In conclusion, we developed a model of endotoxin-induced emphysema exacerbation that affected not only the lungs but also the heart and diaphragm, thus resembling several features of human disease. This model of emphysema should allow preclinical testing of novel therapies with potential for translation into clinical practice.

Effects of Bone Marrow Mesenchymal Stromal Cell Therapy in Experimental Cutaneous Leishmaniasis in BALB/c Mice Induced by Leishmania amazonensis.

Cutaneous leishmaniasis remains both a public health and a therapeutic challenge. To date, no ideal therapy for cutaneous leishmaniasis has been identified, and no universally accepted therapeutic regimen and approved vaccines are available. Due to the mesenchymal stromal cell (MSC) immunomodulatory capacity, they have been applied in a wide variety of disorders, including infectious, inflammatory, and allergic diseases. We evaluated the potential effects of bone marrow MSC therapy in a murine model of cutaneous leishmaniasis. In vitro, coculture of infected macrophages with MSC increased parasite load on macrophages in comparison with controls (macrophages without MSCs). In vivo, BALB/c mice were infected with 2 × 106Leishmania amazonensis (Josefa strain) promastigotes in the footpad. 7 and 37 days after infection, animals were treated with 1 × 105 MSCs, either intralesional (i.l.), i.e., in the same site of infection, or intravenously (i.v.), through the external jugular vein. Control animals received the same volume (50 µL) of phosphate-buffered saline by i.l. or i.v. routes. The lesion progression was assessed by its thickness measured by pachymetry. Forty-two days after infection, animals were euthanized and parasite burden in the footpad and in the draining lymph nodes was quantified by the limiting dilution assay (LDA), and spleen cells were phenotyped by flow cytometry. No significant difference was observed in lesion progression, regardless of the MSC route of administration. However, animals treated with i.v. MSCs presented a significant increase in parasite load in comparison with controls. On the other hand, no harmful effect due to MSCs i.l. administered was observed. The spleen cellular profile analysis showed an increase of IL-10 producing T CD4+ and TCD8+ cells in the spleen only in mice treated with i.v. MSC. The excessive production of IL-10 could be associated with the disease-aggravating effects of MSC therapy when intravenously administered. As a conclusion, in the current murine model of L. amazonensis-induced cutaneous disease, MSCs did not control the damage of cutaneous disease and, depending on the administration route, it could result in deleterious effects.

Therapeutic effects of bone marrow-derived mononuclear cells from healthy or silicotic donors on recipient silicosis mice.

BACKGROUND: Administration of bone marrow mononuclear cells (BMMCs) modulates lung inflammation and fibrosis in experimental silicosis. However, no studies have evaluated whether silicosis affects the efficacy of autologous BMMCs treatment. We hypothesized that BMMCs obtained from healthy or silicotic mice may improve lung function, but they might affect the inflammatory and fibrotic processes differently in experimental silicosis. METHODS: C57BL/6 mice were randomly divided into control (C) and silicosis (SIL) groups. Mice in the SIL group were instilled with silica particles intratracheally; the C animals received saline using the same protocol. On day 15, the animals were treated with saline (Sal) or BMMCs (2 × 106 cells) from healthy (BMMC-healthy) and silicotic (BMMC-sil) donors. Lung mechanics were measured, and lungs were collected for histology and molecular biology analysis. RESULTS: BMMCs obtained from healthy and silicotic donors presented similar percentages of cell populations. 99mTc-BMMCs tracking revealed preferential migration of cells to the liver, and only a few GFP+ BMMCs were observed in lung tissue 24 h after treatment, regardless of donor type. Both the SIL-BMMC-healthy and SIL-BMMC-sil groups showed improvement in lung function, a reduction in the fractional area of granuloma, and a decrease in the number of mononuclear and apoptotic cells in lung parenchyma. In addition, the number of F4/80+ macrophages, the levels of interleukin-1 beta and transforming growth factor beta, and collagen fiber content in granuloma were reduced in SIL-BMMC-healthy mice, whereas mRNA expression of MMP-9 and procollagen I and III was reduced in the SIL-BMMC-sil group. CONCLUSIONS: Administration of BMMCs from healthy and silicotic donors reduced lung inflammation and fibrosis, thus improving lung function. In addition, BMMC-healthy exhibited a greater improvement in lung morpho-functional changes in murine model of silicosis.

Expanded endothelial progenitor cells mitigate lung injury in septic mice.

Endothelial progenitor cells (EPCs) improve survival and reduce organ failure in cecal ligation and puncture-induced sepsis; however, expanded EPCs may represent an even better approach for vascular repair. To date, no study has compared the effects of non-expanded EPCs (EPC-NEXP) with those of expanded EPCs (EPC-EXP) and mesenchymal stromal cells of human (MSC-HUMAN) and mouse (MSC-MICE) origin in experimental sepsis. One day after cecal ligation and puncture sepsis induction, BALB/c mice were randomized to receive saline, EPC-EXP, EPC-NEXP, MSC-HUMAN or MSC-MICE (1 × 10(5)) intravenously. EPC-EXP, EPC-NEXP, MSC-HUMAN, and MSC-MICE displayed differences in phenotypic characterization. On days 1 and 3, cecal ligation and puncture mice showed decreased survival rate, and increased elastance, diffuse alveolar damage, and levels of interleukin (IL)-1ß, IL-6, IL-10, tumor necrosis factor-α, vascular endothelial growth factor, and platelet-derived growth factor in lung tissue. EPC-EXP and MSC-HUMAN had reduced elastance, diffuse alveolar damage, and platelet-derived growth factor compared to no-cell treatment. Tumor necrosis factor-α levels decreased in the EPC-EXP, MSC-HUMAN, and MSC-MICE groups. IL-1ß levels decreased in the EPC-EXP group, while IL-10 decreased in the MSC-MICE. IL-6 levels decreased both in the EPC-EXP and MSC-MICE groups. Vascular endothelial growth factor levels were reduced regardless of therapy. In conclusion, EPC-EXP and MSC-HUMAN yielded better lung function and reduced histologic damage in septic mice.

Intravenous glutamine administration reduces lung and distal organ injury in malnourished rats with sepsis.

Malnutrition is a risk factor for infection, compromising immune response. Glutamine (Gln) protects the lungs and distal organs in well-nourished septic and nonseptic conditions; however, no study to date has analyzed the effects of Gln in the presence of sepsis and malnutrition. In the present work, we tested the hypothesis that early therapy with intravenous Gln prevents lung and distal organ damage in septic malnourished rats. Protein-energy malnutrition was induced in male Wistar rats for 4 weeks. At the end of 4 weeks, malnourished animals were assigned to a sepsis-inducing cecal ligation and puncture group or a sham surgery group. One hour after surgery, animals were given saline (Sal) or L-alanyl-L-glutamine (Gln) intravenously. In addition, a control group (C) was set up with rats fed ad libitum, not submitted to surgery or treatment. Forty-eight hours after surgery, in malnutrition-sham rats, Gln therapy lessened neutrophil lung infiltration and apoptosis in lung and liver. In malnutrition-cecal ligation and puncture rats, Gln therapy yielded (a) reduced static lung elastance, alveolar collapse, inflammation (neutrophil infiltration, interleukin 6), and collagen deposition; (b) repair of types I and II epithelial cells; (c) no significant changes in heat shock protein 70 expression or heat shock factor 1 phosphorylation; (d) a greater number of M1 and M2 macrophages in lung tissue; and (e) less apoptosis in the lung, kidney, small intestine, and liver. In conclusion, early therapy with intravenous Gln reduced inflammation, fibrosis, and apoptosis, minimizing lung and distal organ injury, in septic malnourished rats. These beneficial effects may be associated with macrophage activation in the lung.

Insult-dependent effect of bone marrow cell therapy on inflammatory response in a murine model of extrapulmonary acute respiratory distress syndrome.

INTRODUCTION: Administration of bone marrow-derived cells produces beneficial effects in experimental extrapulmonary acute respiratory distress syndrome (ARDS). However, there are controversies regarding the effects of timing of cell administration and initial insult severity on inflammatory response. We evaluated the effects of bone marrow-derived mononuclear cells (BMDMC) in two models of extrapulmonary ARDS once lung morphofunctional changes had already been installed. METHODS: BALB/c mice received lipopolysaccharide (LPS) intraperitoneally (5 mg/kg in 0.5 ml saline) or underwent cecal ligation and puncture (CLP). Control mice received saline intraperitoneally (0.5 ml) or underwent sham surgery. At 24 hours, groups were further randomized to receive saline or BMDMC (2 × 10(6)) intravenously. Lung mechanics, histology, and humoral and cellular parameters of lung inflammation and remodeling were analyzed 1, 3 and 7 days after ARDS induction. RESULTS: BMDMC therapy led to improved survival in the CLP group, reduced lung elastance, alveolar collapse, tissue and bronchoalveolar lavage fluid cellularity, collagen fiber content, and interleukin-1ß and increased chemokine (keratinocyte-derived chemokine and monocyte chemotactic protein-1) expression in lung tissue regardless of the experimental ARDS model. Intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression in lung tissue increased after cell therapy depending on the insult (LPS or CLP). CONCLUSIONS: BMDMC therapy at day 1 successfully reduced lung inflammation and remodeling, thus contributing to improvement of lung mechanics in both extrapulmonary ARDS models. Nevertheless, the different inflammatory responses induced by LPS and CLP resulted in distinct effects of BMDMC therapy. These data may be useful in the clinical setting, as they suggest that the type of initial insult plays a key role in the outcome of treatment.

Impact of Bacillus Calmette-Guérin Moreau vaccine on lung remodeling in experimental asthma.

We analyzed the effects of different administration routes and application times of the BCG-Moreau strain on airway and lung inflammation and remodeling in a murine model of allergic asthma. BALB/c mice (n=168) were divided into two groups. The first group received BCG-Moreau strain while the second group received saline using the same protocol. BCG or saline were intradermally or intranasally injected one or two months before the induction of asthma. Mice were further sensitized and challenged with ovalbumin or received saline. Twenty-four hours after the last challenge, BCG prevented the triggering of pro-inflammatory cytokines, probably by increasing Foxp3 and interleukin (IL)-10, modulating eosinophil infiltration and collagen fiber deposition, thus reducing airway hyperresponsiveness. In conclusion, BCG-Moreau prevented lung remodeling in the present model of allergic asthma, regardless of administration route and time of vaccination. These beneficial effects may be related to the increase in regulatory T cells and to IL-10 production in tandem with decreased Th2 cytokines (IL-4, IL-5, and IL-13).

Terapia com surfactante na síndrome do desconforto respiratório agudo: prós e contras / Surfactant therapy in acute respiratory distress syndrome: pros and cons

A síndrome do desconforto respiratório agudo (SDRA) acarreta disfunção quantitativa e qualitativa do sistema de surfactante pulmonar endógeno, levando à disfunção respiratória. Nesse contexto, a administração de surfactante pode vir a ser uma opção de terapêutica na SDRA, com importante impacto sobre a função pulmonar e a oxigenação. O presente artigo apresenta uma breve revisão acerca do potencial terapêutico do surfactante na SDRA. Para tal, foi realizada uma revisão sistemática da literatura, através das bases de dados MedLine, Scielo e Lilacs, onde foram incluídos artigos dos últimos anos, referentes ao assunto. Os artigos incluídos abordaram a terapêutica de reposição do surfactante em estudos experimentais e clínicos, assim como revisões sistemáticas sobre aspectos bioquímicos e fisiológicos do surfactante e da SDRA. Apesar de diversos estudos experimentais terem evidenciado efeitos benéficos com o uso do surfactante exógeno na SDRA, proporcionando melhora da função pulmonar, os trabalhos clínicos vêm apresentando resultados controversos. Entretanto, a administração de novos surfactantes exógenos tem apresentado resultados promissores. Concluindo, o uso do surfactante exógeno pode vir a fazer parte do tratamento dos pacientes portadores de SDRA.

Acute respiratory distress syndrome (ARDS) causes changes in pulmonary surfactant leading to respiratory dysfunction. In this context, the administration of surfactant may become a therapeutic option for ARDS with significant impact on lung function and oxygenation. This article presents a brief review regarding the potential of surfactant therapy in acute respiratorydistress syndrome. We performed a systematic review of the literature using the following databases: MedLine,SciELO and Lilacs. Experimental and clinical studies related to surfactant therapy in ARDS as well as systematic reviews of the biochemical and physiological aspects of surfactant were included in the present manuscript. Despite several experimental studies have shown beneficial effects with the use of surfactant in ARDS, leading to improvement in lung function, clinicalstudies have shown controversial results. However, the use of new surfactants has providing promising results. Therefore, use of surfactant can become part of ARDS patient treatment.