Effects of bone marrow-derived mononuclear cells on airway and lung parenchyma remodeling in a murine model of chronic allergic inflammation

Collagen-Mesenchymal Stem Cell Microspheres Embedded in Hyaluronic Acid Solutions as Biphasic Stem Niche Delivery Systems for Pulmonary Differentiation

Cell therapy has the potential to become a feasible solution for several diseases, such as those related to the lungs and airways, considering the more beneficial intratracheal administration route. However, in lung diseases, an impaired pulmonary extracellular matrix (ECM) precludes injury resolution with a faulty engraftment of mesenchymal stem cells (MSCs) at the lung level. Furthermore, a shielding strategy to avoid cell damage as well as cell loss due to backflow through the injection path is required. Here, an approach to deliver cells encapsulated in a biomimetic stem niche is used, in which the interplay between cells and physiological lung ECM constituents, such as collagen and hyaluronic acid (HA), can occur. To this aim, a biphasic delivery system based on MSCs encapsulated in collagen microspheres (mCOLLs) without chemical modification and embedded in an injectable HA solution has been developed. Such biphasic delivery systems can both increase the mucoadhesive properties at the site of interest and improve cell viability and pulmonary differentiation. Rheological results showed a similar viscosity at high shear rates compared to the MSC suspension used in intratracheal administration. The size of the mCOLLs can be controlled, resulting in a lower value of 200 μm, suitable for delivery in alveolar sacs. Biological results showed that mCOLLs maintained good cell viability, and when they were suspended in lung medium implemented with low molecular weight HA, the differentiation ability of the MSCs was further enhanced compared to their differentiation ability in only lung medium. Overall, the results showed that this strategy has the potential to improve the delivery and viability of MSCs, along with their differentiation ability, in the pulmonary lineage.

Immunomodulatory effect of IL-2 induced bone marrow mononuclear cell therapy on control of allergic asthma

Asthma is a chronic airway disease. Allergic reactions and T helper (h)2 immune response play a key role in asthma occurrence. Cell therapy can control inflammation and remodeling responses in allergic asthma, and cytokines can change this effect. Therefore, in this study, the effect of treated cell therapy with IL-2 to control allergic asthma was studied. Bone marrow cells were extracted and co-cultured with IL-2 and the cells were used via intra-tracheal administration in allergic asthma mice. Levels of IL-4, IL-5, IL-13, Leukotriene B4 and C4, and remodeling factors were measured. At least, a histopathology test of lung tissue was done. Type2 cytokines, leukotrienes, remodeling factors, mucus secretion, goblet cell hyperplasia, peri-bronchial and peri-vascular inflammation were significantly (p˂0.05) decreased by treating with bone marrow-derived mononuclear cells (BMDMCs) and IL-2-BMDMCs. Treatment with IL-2-BMDMCs could significantly decrease IL-13, transforming growth factor (TGF)-β, HP levels, and mucus secretion (p˂0.05) compared to BMDMCs treatment. In this study, BMDMCs and IL-2-BMDMCs therapy could decrease inflammation, allergic, and remodeling factors in allergic asthma. Cell therapy with BMDMCs had a strong and notable effect on the control of allergic asthma pathophysiology when co-cultured and used with IL-2.

Mesenchymal stromal cells protect against vascular damage and depression-like behavior in mice surviving cerebral malaria

BACKGROUND

Malaria is one of the most critical global infectious diseases. Severe systemic inflammatory diseases, such as cerebral malaria, lead to the development of cognitive and behavioral alterations, such as learning disabilities and loss of memory capacity, as well as increased anxiety and depression. The consequences are profound and usually contribute to reduce the patient's quality of life. There are no therapies to treat the neurological sequelae of cerebral malaria. Mesenchymal stromal cells (MSCs) may be an alternative, since they have been used as therapy for neurodegenerative diseases and traumatic lesions of the central nervous system. So far, no study has investigated the effects of MSC therapy on the blood-brain barrier, leukocyte rolling and adherence in the brain, and depression like-behavior in experimental cerebral malaria.

METHODS

Male C57BL/6 mice were infected with Plasmodium berghei ANKA (PbA, 1 × 106 PbA-parasitized red blood cells, intraperitoneally). At day 6, PbA-infected animals received chloroquine (25 mg/kg orally for seven consecutive days) as the antimalarial treatment and were then randomized to receive MSCs (1 × 105 cells in 0.05 ml of saline/mouse) or saline (0.05 ml) intravenously. Parasitemia, clinical score, and survival rate were analyzed throughout the experiments. Evans blue assay was performed at 6, 7, and 15 days post-infection (dpi). Behavioral tests were performed at 5 and 15 dpi. Intravital microscopy experiments and brain-derived neurotrophic factor (BDNF) protein expression analyses were performed at 7 dpi, whereas inflammatory mediators were measured at 15 dpi. In vitro, endothelial cells were used to evaluate the effects of conditioned media derived from MSCs (CMMSC) on cell viability by lactate dehydrogenase (LDH) release.

RESULTS

PbA-infected mice presented increased parasitemia, adherent leukocytes, blood-brain barrier permeability, and reduced BDNF protein levels, as well as depression-like behavior. MSCs mitigated behavioral alterations, restored BDNF and transforming growth factor (TGF)-β protein levels, and reduced blood-brain barrier dysfunction and leukocyte adhesion in the brain microvasculature. In a cultured endothelial cell line stimulated with heme, CMMSC reduced LDH release, suggesting a paracrine mechanism of action.

CONCLUSION

A single dose of MSCs as adjuvant therapy protected against vascular damage and improved depression-like behavior in mice that survived experimental cerebral malaria.

Nanoparticle-based thymulin gene therapy therapeutically reverses key pathology of experimental allergic asthma

Despite long-standing efforts to enhance care for chronic asthma, symptomatic treatments remain the only option to manage this highly prevalent and debilitating disease. We demonstrate that key pathology of allergic asthma can be almost completely resolved in a therapeutic manner by inhaled gene therapy. After the disease was fully and stably established, we treated mice intratracheally with a single dose of thymulin-expressing plasmids delivered via nanoparticles engineered to have a unique ability to penetrate the airway mucus barrier. Twenty days after the treatment, we found that all key pathologic features found in the asthmatic lung, including chronic inflammation, pulmonary fibrosis, and mechanical dysregulation, were normalized. We conducted tissue- and cell-based analyses to confirm that the therapeutic intervention was mediated comprehensively by anti-inflammatory and antifibrotic effects of the therapy. We believe that our findings open a new avenue for clinical development of therapeutically effective gene therapy for chronic asthma.

Deconstructing tissue engineered trachea: Assessing the role of synthetic scaffolds, segmental replacement and cell seeding on graft performance

The ideal construct for tracheal replacement remains elusive in the management of long segment airway defects. Tissue engineered tracheal grafts (TETG) have been limited by the development of graft stenosis or collapse, infection, or lack of an epithelial lining. We applied a mouse model of orthotopic airway surgery to assess the impact of three critical barriers encountered in clinical applications: the scaffold, the extent of intervention, and the impact of cell seeding and characterized their impact on graft performance. First, synthetic tracheal scaffolds electrospun from polyethylene terephthalate / polyurethane (PET/PU) were orthotopically implanted in anterior tracheal defects of C57BL/6 mice. Scaffolds demonstrated complete coverage with ciliated respiratory epithelium by 2 weeks. Epithelial migration was accompanied by macrophage infiltration which persisted at long term (>6 weeks) time points. We then assessed the impact of segmental tracheal implantation using syngeneic trachea as a surrogate for the ideal tracheal replacement. Graft recovery involved local upregulation of epithelial progenitor populations and there was no evidence of graft stenosis or necrosis. Implantation of electrospun synthetic tracheal scaffold for segmental replacement resulted in respiratory distress and required euthanasia at an early time point. There was limited epithelial coverage of the scaffold with and without seeded bone marrow-derived mononuclear cells (BM-MNCs). We conclude that synthetic scaffolds support re-epithelialization in orthotopic patch implantation, syngeneic graft integration occurs with focal repair mechanisms, however epithelialization in segmental synthetic scaffolds is limited and is not influenced by cell seeding. STATEMENT OF SIGNIFICANCE: The life-threatening nature of long-segment tracheal defects has led to clinical use of tissue engineered tracheal grafts in the last decade for cases of compassionate use. However, the ideal tracheal reconstruction using tissue-engineered tracheal grafts (TETG) has not been clarified. We addressed the core challenges in tissue engineered tracheal replacement (re-epithelialization and graft patency) by defining the role of cell seeding with autologous bone marrow-derived mononuclear cells, the mechanism of respiratory epithelialization and proliferation, and the role of the inflammatory immune response in regeneration. This research will facilitate comprehensive understanding of cellular regeneration and neotissue formation on TETG, which will permit targeted therapies for accelerating re-epithelialization and attenuating stenosis in tissue engineered airway replacement.

An Official American Thoracic Society Workshop Report 2015. Stem Cells and Cell Therapies in Lung Biology and Diseases

The University of Vermont College of Medicine, in collaboration with the NHLBI, Alpha-1 Foundation, American Thoracic Society, Cystic Fibrosis Foundation, European Respiratory Society, International Society for Cellular Therapy, and the Pulmonary Fibrosis Foundation, convened a workshop, "Stem Cells and Cell Therapies in Lung Biology and Lung Diseases," held July 27 to 30, 2015, at the University of Vermont. The conference objectives were to review the current understanding of the role of stem and progenitor cells in lung repair after injury and to review the current status of cell therapy and ex vivo bioengineering approaches for lung diseases. These are all rapidly expanding areas of study that both provide further insight into and challenge traditional views of mechanisms of lung repair after injury and pathogenesis of several lung diseases. The goals of the conference were to summarize the current state of the field, discuss and debate current controversies, and identify future research directions and opportunities for both basic and translational research in cell-based therapies for lung diseases. This 10th anniversary conference was a follow up to five previous biennial conferences held at the University of Vermont in 2005, 2007, 2009, 2011, and 2013. Each of those conferences, also sponsored by the National Institutes of Health, American Thoracic Society, and respiratory disease foundations, has been important in helping guide research and funding priorities. The major conference recommendations are summarized at the end of the report and highlight both the significant progress and major challenges in these rapidly progressing fields.

Collection, processing and freezing of equine bone marrow cells

There is no consensus on aspects of equine bone marrow collection and processing. The study aimed to describe the collection of large volumes of bone marrow from horses of advanced age, with emphasis on bone marrow mononuclear cells (BMMCs) recovery and viability after cryopreservation. Fourteen horses, aged 3-24 years, were divided into three experiments. E1 studied the feasibility of collecting 200 mL from the sternums of horses of advanced age; E2 examined the number of cells obtained from the first and last syringe of each puncture; and E3 investigated the influence of heparin concentration on the prevention of cell aggregation, and cell viability after freezing in liquid nitrogen. Bone marrow aspirations were done with syringes pre-filled with Iscove's modified Dulbecco's medium and different concentrations of sodium heparin. BMMCs were counted, cell viability was determined, and samples were frozen. Bone marrow collection from the sternum is safe, even at large volumes and from horses of advanced age, and the number of cells recovered decreases with successive aspirations (p < 0.0001). Heparin concentration influenced cell aggregation, and recovered cells continued to be commercially viable after 150 days in frozen storage.

Effects of human umbilical cord blood mononuclear cells on respiratory system mechanics in a murine model of neonatal lung injury

BACKGROUND

Mononuclear cells (MNCs) have well-documented beneficial effects in a wide range of adult pulmonary diseases. The effects of human umbilical cord blood-derived MNCs on neonatal lung injury, highly relevant for potential autologous application in preterm newborns at risk for bronchopulmonary dysplasia (BPD), remain incompletely established. The aim of this study was to determine the long-term morphologic and functional effects of systemically delivered MNCs in a murine model of neonatal lung injury.

MATERIALS AND METHODS

MNCs from cryopreserved cord blood (1 × 10⁶ cells per pup) were given intravenously to newborn mice exposed to 90% O₂ from birth; controls received cord blood total nucleated cells (TNCs) or granular cells, or equal volume vehicle buffer (sham controls). In order to avoid immune rejection, we used SCID mice as recipients. Lung mechanics (flexiVent™), engraftment, growth, and alveolarization were evaluated eight weeks postinfusion.

RESULTS

Systemic MNC administration to hyperoxia-exposed newborn mice resulted in significant attenuation of methacholine-induced airway hyperreactivity, leading to reduction of central airway resistance to normoxic levels. These bronchial effects were associated with mild improvement of alveolarization, lung compliance, and elastance. TNCs had no effects on alveolar remodeling and were associated with worsened methacholine-induced bronchial hyperreactivity. Granular cell administration resulted in a marked morphologic and functional emphysematous phenotype, associated with high mortality. Pulmonary donor cell engraftment was sporadic in all groups.

CONCLUSIONS

These results suggest that cord blood MNCs may have a cell type-specific role in therapy of pulmonary conditions characterized by increased airway resistance, such as BPD and asthma. Future studies need to determine the active MNC subtype(s), their mechanisms of action, and optimal purification methods to minimize granular cell contamination.

Fetal mesenchymal stem cells ameliorate acute lung injury in a rat cardiopulmonary bypass model

BACKGROUND

Systemic inflammation after prolonged cardiopulmonary bypass (CPB) can cause serious multiorgan system dysfunction. Mesenchymal stem cells (MSCs) are reported to reduce inflammation and attenuate immune response. We have focused on fetal membrane (FM) as a source to provide a large number of MSCs (FM-MSCs). Allogeneic administration of FM-MSCs has been reported to mitigate autoimmune myocarditis or glomerulonephritis. The aim of this study was to investigate whether allogeneic FM-MSCs attenuate systemic inflammatory responses and lung injury in a rat CPB model.

METHODS

Male Lewis rats (major histocompatibility complex haplotype: RT-1l) were divided randomly into 3 groups (n = 7 each): cannulation alone (sham group), CPB alone (control group), and CPB + MSC (MSC group). An experimental rat CPB model was established, and CPB was maintained for 30 minutes. In the MSC group, MSCs (1 × 10⁶ cells) derived from the FM of ACI rats with a different major histocompatibility complex haplotype (RT-1a) were administrated intravenously before CPB initiation.

RESULTS

Serum concentrations of tumor necrosis factor-α, interleukin-6, and interleukin-1β in the MSC group were significantly lower compared with the control group after CPB. Similarly, mRNA expression of proinflammatory cytokines in the lung was lower in the MSC group. Allogeneic administration of FM-MSCs remarkably decreased the lung injury score, protected alveolar structure, inhibited neutrophil infiltration to the lung interstitium, and stimulated cytoprotective cytokine production in the lung.

CONCLUSIONS

Allogeneic transplantation of FM-MSCs may be a potent strategy to prevent CPB-induced systemic inflammation and acute lung injury by suppressing the expression of inflammatory cytokines and promoting protective factors in the lung.

CD11b+ and Sca-1+ Cells Exert the Main Beneficial Effects of Systemically Administered Bone Marrow-Derived Mononuclear Cells in a Murine Model of Mixed Th2/Th17 Allergic Airway Inflammation

A murine model of severe clinical asthma was used to study which bone marrow-derived mononuclear cells (BMDMCs) are responsible for ameliorating airway hyperresponsiveness and lung inflammation. BMDMCs depleted of either CD11b-positive cells (monocytes, macrophages, dendritic cells) or Sca-1-positive cells (bone marrow-derived mesenchymal stromal cells) were unable to ameliorate these conditions in this model. Depletion of the other cell types did not diminish the ameliorating effects of BMDMC administration.

Systemic administration of bone marrow-derived mononuclear cells (BMDMCs) or bone marrow-derived mesenchymal stromal cells (MSCs) reduces inflammation and airway hyperresponsiveness (AHR) in a murine model of Th2-mediated eosinophilic allergic airway inflammation. However, since BMDMCs are a heterogeneous population that includes MSCs, it is unclear whether the MSCs alone are responsible for the BMDMC effects. To determine which BMDMC population(s) is responsible for ameliorating AHR and lung inflammation in a model of mixed Th2-eosinophilic and Th17-neutrophilic allergic airway inflammation, reminiscent of severe clinical asthma, BMDMCs obtained from normal C57Bl/6 mice were serially depleted of CD45, CD34, CD11b, CD3, CD19, CD31, or Sca-1 positive cells. The different resulting cell populations were then assessed for ability to reduce lung inflammation and AHR in mixed Th2/Th17 allergic airway inflammation induced by mucosal sensitization to and challenge with Aspergillus hyphal extract (AHE) in syngeneic C56Bl/6 mice. BMDMCs depleted of either CD11b-positive (CD11b+) or Sca-1-positive (Sca-1+) cells were unable to ameliorate AHR or lung inflammation in this model. Depletion of the other cell types did not diminish the ameliorating effects of BMDMC administration. In conclusion, in the current model of allergic inflammation, CD11b+ cells (monocytes, macrophages, dendritic cells) and Sca-1+ cells (MSCs) are responsible for the beneficial effects of BMDMCs.

Significance

This study shows that bone marrow-derived mononuclear cells (BMDMCs) are as effective as bone marrow-derived mesenchymal stromal cells (MSCs) in ameliorating experimental asthma. It also demonstrates that not only MSCs present in the pool of BMDMCs are responsible for BMDMCs’ beneficial effects but also monocytes, which are the most important cell population to trigger these effects. All of this is in the setting of a clinically relevant model of severe allergic airways inflammation and thus provides further support for potential clinical use of cell therapy using MSCs, BMDMCs, and also adult cells such as monocytes in patients with severe asthma.

The tyrosine kinase inhibitor dasatinib reduces lung inflammation and remodelling in experimental allergic asthma

BACKGROUND AND PURPOSE

Asthma is characterized by chronic lung inflammation and airway hyperresponsiveness. Despite recent advances in understanding of its pathophysiology, asthma remains a major public health problem, and new therapeutic strategies are urgently needed. In this context, we sought to ascertain whether treatment with the TK inhibitor dasatinib might repair inflammatory and remodelling processes, thus improving lung function, in a murine model of asthma.

EXPERIMENTAL APPROACH

Animals were sensitized and subsequently challenged, with ovalbumin (OVA) or saline. Twenty-four hours after the last challenge, animals were treated with dasatinib, dexamethasone, or saline, every 12 h for 7 consecutive days. Twenty-four hours after the last treatment, the animals were killed, and data were collected. Lung structure and remodelling were evaluated by morphometric analysis, immunohistochemistry, and transmission electron microscopy of lung sections. Inflammation was assessed by cytometric analysis and ELISA, and lung function was evaluated by invasive whole-body plethysmography.

KEY RESULTS

In OVA mice, dasatinib, and dexamethasone led to significant reductions in airway hyperresponsiveness. Dasatinib was also able to attenuate alveolar collapse, contraction index, and collagen fibre deposition, as well as increasing elastic fibre content, in OVA mice. Concerning the inflammatory process, dasatinib reduced inflammatory cell influx to the airway and lung-draining mediastinal lymph nodes, without inducing the thymic atrophy promoted by dexamethasone.

CONCLUSIONS AND IMPLICATIONS

In this model of allergic asthma, dasatinib effectively blunted the inflammatory and remodelling processes in asthmatic lungs, enhancing airway repair and thus improving lung mechanics.

An official American Thoracic Society workshop report: stem cells and cell therapies in lung biology and diseases

The University of Vermont College of Medicine and the Vermont Lung Center, in collaboration with the NHLBI, Alpha-1 Foundation, American Thoracic Society, European Respiratory Society, International Society for Cell Therapy, and the Pulmonary Fibrosis Foundation, convened a workshop, "Stem Cells and Cell Therapies in Lung Biology and Lung Diseases," held July 29 to August 1, 2013 at the University of Vermont. The conference objectives were to review the current understanding of the role of stem and progenitor cells in lung repair after injury and to review the current status of cell therapy and ex vivo bioengineering approaches for lung diseases. These are all rapidly expanding areas of study that both provide further insight into and challenge traditional views of mechanisms of lung repair after injury and pathogenesis of several lung diseases. The goals of the conference were to summarize the current state of the field, discuss and debate current controversies, and identify future research directions and opportunities for both basic and translational research in cell-based therapies for lung diseases. This conference was a follow-up to four previous biennial conferences held at the University of Vermont in 2005, 2007, 2009, and 2011. Each of those conferences, also sponsored by the National Institutes of Health, American Thoracic Society, and Respiratory Disease Foundations, has been important in helping guide research and funding priorities. The major conference recommendations are summarized at the end of the report and highlight both the significant progress and major challenges in these rapidly progressing fields.

Regular and moderate aerobic training before allergic asthma induction reduces lung inflammation and remodeling

Experimental studies have reported that aerobic exercise after asthma induction reduces lung inflammation and remodeling. Nevertheless, no experimental study has analyzed whether regular/moderate aerobic training before the induction of allergic asthma may prevent these inflammatory and remodeling processes. For this purpose, BALB/c mice (n = 96) were assigned into non-trained and trained groups. Trained animals ran on a motorized treadmill at moderate intensity, 30 min/day, 3 times/week, for 8 weeks, and were further randomized into subgroups to undergo ovalbumin sensitization and challenge or receive saline using the same protocol. Aerobic training continued until the last challenge. Twenty-four hours after challenge, compared to non-trained animals, trained mice exhibited: (a) increased systolic output and left ventricular mass on echocardiography; (b) improved lung mechanics; (c) decreased smooth muscle actin expression and collagen fiber content in airways and lung parenchyma; (d) decreased transforming growth factor (TGF)-β levels in bronchoalveolar lavage fluid (BALF) and blood; (e) increased interferon (IFN)-γ in BALF and interleukin (IL)-10 in blood; and (f) decreased IL-4 and IL-13 in BALF. In conclusion, regular/moderate aerobic training prior to allergic asthma induction reduced inflammation and remodeling, perhaps through increased IL-10 and IFN-γ in tandem with decreased Th2 cytokines.

Stem cells in animal asthma models: a systematic review

BACKGROUND AIMS

Asthma control frequently falls short of the goals set in international guidelines. Treatment options for patients with poorly controlled asthma despite inhaled corticosteroids and long-acting β-agonists are limited, and new therapeutic options are needed. Stem cell therapy is promising for a variety of disorders but there has been no human clinical trial of stem cell therapy for asthma. We aimed to systematically review the literature regarding the potential benefits of stem cell therapy in animal models of asthma to determine whether a human trial is warranted.

METHODS

The MEDLINE and Embase databases were searched for original studies of stem cell therapy in animal asthma models.

RESULTS

Nineteen studies were selected. They were found to be heterogeneous in their design. Mesenchymal stromal cells were used before sensitization with an allergen, before challenge with the allergen and after challenge, most frequently with ovalbumin, and mainly in BALB/c mice. Stem cell therapy resulted in a reduction of bronchoalveolar lavage fluid inflammation and eosinophilia as well as Th2 cytokines such as interleukin-4 and interleukin-5. Improvement in histopathology such as peribronchial and perivascular inflammation, epithelial thickness, goblet cell hyperplasia and smooth muscle layer thickening was universal. Several studies showed a reduction in airway hyper-responsiveness.

CONCLUSIONS

Stem cell therapy decreases eosinophilic and Th2 inflammation and is effective in several phases of the allergic response in animal asthma models. Further study is warranted, up to human clinical trials.

Cell-based therapies for the acute respiratory distress syndrome

PURPOSE OF REVIEW

Acute respiratory distress syndrome (ARDS) is a multifaceted lung disease with no current effective therapy. Many clinical trials using conventional pharmacologic therapies have failed, suggesting the need to examine alternative approaches. Thus, attention has focused on the therapeutic potential of cell-based therapies for ARDS, with promising results demonstrated in relevant preclinical disease models. We review data concerning the therapeutic promise of cell-based therapies for ARDS.

RECENT FINDINGS

Recent experimental studies provide further evidence for the potential of cell-based therapies in ARDS. A number of cell types, particularly mesenchymal stem/stromal cells (MSCs), bone marrow-derived mononuclear cells, endothelial progenitor cells, and embryonic stem cells have been demonstrated to reduce mortality and modulate the inflammatory and remodeling processes in relevant preclinical ARDS models. Multiple insights have emerged in regard to the mechanisms by which cell therapies - particularly MSCs - exert their effects, with evidence supporting direct cell-mediated and paracrine-mediated mechanisms of action. Diverse paracrine mechanisms exist, including the release of cytokines, growth factors (such as keratinocyte growth factor), and antimicrobial peptides, and transfer of cellular contents such as peptides, nucleic acids, and mitochondria via either microvesicular or direct cell-cell contact-mediated transfer.

SUMMARY

Cell-based therapies offer considerable promise for the treatment of ARDS. While MSC-based therapies are being rapidly advanced toward clinical testing, clear therapeutic potential exists for other cell types for ARDS. A greater understanding of current knowledge gaps should further enhance the therapeutic potential of cell-based therapies for ARDS.

Effects of bone marrow mononuclear cells from healthy or ovalbumin-induced lung inflammation donors on recipient allergic asthma mice

Introduction

Asthma is characterized by a chronic inflammatory process which may lead to several changes in bone marrow cell composition. We hypothesized that bone marrow mononuclear cells (BMMCs) obtained from ovalbumin (OVA)-induced lung inflammation mice may promote different effects compared to BMMCs from healthy donors in a model of allergic asthma.

Methods

C57BL/6 mice were randomly assigned to two groups. In the OVA group, mice were sensitized and challenged with ovalbumin, while healthy animals (control group) received saline using the same protocol. BMMCs were analyzed by flow cytometry 24 hours after the last challenge. After BMMC characterization, another group of OVA mice were further randomized into three subgroups to receive intratracheal saline (BMMC-SAL), BMMCs from control or BMMCs from OVA mice (BMMC-Control and BMMC-OVA, respectively; 2x10⁶ cells/mouse), 24 hours after the last challenge.

Results

BMMC-OVA exhibited an increased percentage of eosinophils, monocytes and hematopoietic precursors, while mesenchymal stem cells decreased, as compared with BMMC-Control. BMMCs from both donor groups reduced airway resistance, alveolar collapse, bronchoconstriction index, eosinophil infiltration, collagen fiber content in alveolar septa and levels of interleukin (IL)-4, IL-5, IL-13, interferon-γ, transforming growth factor-β, and vascular endothelial growth factor in lung homogenates. However, the benefits of BMMCs were significantly more pronounced when cells were obtained from control donors.

Conclusion

Both BMMC-Control and BMMC-OVA reduced the inflammatory and remodeling processes; nevertheless, BMMC-Control led to a greater improvement in lung morphofunction, which may be due to different BMMC composition and/or properties.

Stem cells, cell therapies, and bioengineering in lung biology and diseases. Comprehensive review of the recent literature 2010-2012

A conference, "Stem Cells and Cell Therapies in Lung Biology and Lung Diseases," was held July 25 to 28, 2011 at the University of Vermont to review the current understanding of the role of stem and progenitor cells in lung repair after injury and to review the current status of cell therapy and ex vivo bioengineering approaches for lung diseases. These are rapidly expanding areas of study that provide further insight into and challenge traditional views of mechanisms of lung repair after injury and pathogenesis of several lung diseases. The goals of the conference were to summarize the current state of the field, to discuss and debate current controversies, and to identify future research directions and opportunities for basic and translational research in cell-based therapies for lung diseases. The goal of this article, which accompanies the formal conference report, is to provide a comprehensive review of the published literature in lung regenerative medicine from the last conference report through December 2012.

DNA nanoparticle-mediated thymulin gene therapy prevents airway remodeling in experimental allergic asthma

Thymulin has been shown to present anti-inflammatory and anti-fibrotic properties in experimental lung diseases. We hypothesized that a biologically active thymulin analog gene, methionine serum thymus factor, delivered by highly compacted DNA nanoparticles may prevent lung inflammation and remodeling in a mouse model of allergic asthma. The DNA nanoparticles are composed of a single molecule of plasmid DNA compacted with block copolymers of poly-L-lysine and polyethylene glycol (CK30PEG), which have been found safe in a human phase I/II clinical trial. Thymulin plasmids were detected in the lungs of ovalbumin-challenged asthmatic mice up to 27days after administration of DNA nanoparticles carrying thymulin plasmids. A single dose of DNA nanoparticles carrying thymulin plasmids prevented lung inflammation, collagen deposition and smooth muscle hypertrophy in the lungs of a murine model of ovalbumin-challenged allergic asthma, leading to improved lung mechanics. In the present model of chronic allergic asthma, highly compacted DNA nanoparticles using thymulin analog gene modulated the inflammatory and remodeling processes improving lung mechanics.

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 × 10⁶) 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-1β 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.

Paracrine effects and heterogeneity of marrow-derived stem/progenitor cells: relevance for the treatment of respiratory diseases

Stem cell-based treatment may represent a hope for the treatment of acute lung injury and pulmonary fibrosis, and other chronic lung diseases, such as cystic fibrosis, asthma and chronic obstructive pulmonary disease (COPD). It is well established in preclinical models that bone marrow-derived stem and progenitor cells exert beneficial effects on inflammation, immune responses and repairing of damage in virtually all lung-borne diseases. While it was initially thought that the positive outcome was due to a direct engraftment of these cells into the lung as endothelial and epithelial cells, paracrine factors are now considered the main mechanism through which stem and progenitor cells exert their therapeutic effect. This knowledge has led to the clinical use of marrow cells in pulmonary hypertension with endothelial progenitor cells (EPCs) and in COPD with mesenchymal stromal (stem) cells (MSCs). Bone marrow-derived stem cells, including hematopoietic stem/progenitor cells, MSCs, EPCs and fibrocytes, encompass a wide array of cell subsets with different capacities of engraftment and injured tissue-regenerating potential. The characterization/isolation of the stem cell subpopulations represents a major challenge to improve the efficacy of transplantation protocols used in regenerative medicine and applied to lung disorders.

Bone marrow-derived mononuclear cells vs. mesenchymal stromal cells in experimental allergic asthma

We compared the effects of bone marrow-derived mononuclear cells (BMMCs) and mesenchymal stromal cells (MSCs) on airway inflammation and remodeling and lung mechanics in experimental allergic asthma. C57BL/6 mice were sensitized and challenged with ovalbumin (OVA group). A control group received saline using the same protocol. Twenty-four hours after the last challenge, groups were further randomized into subgroups to receive saline, BMMCs (2×10(6)) or MSCs (1×10(5)) intratracheally. BMMC and MSC administration decreased cell infiltration, bronchoconstriction index, alveolar collapse, collagen fiber content in the alveolar septa, and interleukin (IL)-4, IL-13, transforming growth factor (TGF)-β and vascular endothelial growth factor (VEGF) levels compared to OVA-SAL. Lung function, alveolar collapse, collagen fiber deposition in alveolar septa, and levels of TGF-β and VEGF improved more after BMMC than MSC therapy. In conclusion, intratracheal BMMC and MSC administration effectively modulated inflammation and fibrogenesis in an experimental model of asthma, but BMMCs was associated with greater benefit in terms of reducing levels of fibrogenesis-related growth factors.

Bone marrow mononuclear cell therapy in experimental allergic asthma: intratracheal versus intravenous administration

We hypothesized that the route of administration would impact the beneficial effects of bone marrow-derived mononuclear cell (BMDMC) therapy on the remodelling process of asthma. C57BL/6 mice were randomly assigned to two main groups. In the OVA group, mice were sensitized and challenged with ovalbumin, while the control group received saline using the same protocol. Twenty-four hours before the first challenge, control and OVA animals were further randomized into three subgroups to receive saline (SAL), BMDMCs intravenously (2×10(6)), or BMDMCs intratracheally (2×10(6)). The following changes were induced by BMDMC therapy in OVA mice regardless of administration route: reduction in resistive and viscoelastic pressures, static elastance, eosinophil infiltration, collagen fibre content in airways and lung parenchyma; and reduction in the levels of interleukin (IL)-4, IL-13, transforming growth factor-β and vascular endothelial growth factor. In conclusion, BMDMC modulated inflammatory and remodelling processes regardless of administration route in this experimental model of allergic asthma.

Engineering airway epithelium

Airway epithelium is constantly presented with injurious signals, yet under healthy circumstances, the epithelium maintains its innate immune barrier and mucociliary elevator function. This suggests that airway epithelium has regenerative potential (I. R. Telford and C. F. Bridgman, 1990). In practice, however, airway regeneration is problematic because of slow turnover and dedifferentiation of epithelium thereby hindering regeneration and increasing time necessary for full maturation and function. Based on the anatomy and biology of the airway epithelium, a variety of tissue engineering tools available could be utilized to overcome the barriers currently seen in airway epithelial generation. This paper describes the structure, function, and repair mechanisms in native epithelium and highlights specific and manipulatable tissue engineering signals that could be of great use in the creation of artificial airway epithelium.

Protective effects of bone marrow mononuclear cell therapy on lung and heart in an elastase-induced emphysema model

We hypothesized that bone marrow-derived mononuclear cell (BMDMC) therapy protects the lung and consequently the heart in experimental elastase-induced emphysema. Twenty-four female C57BL/6 mice were intratracheally instilled with saline (C group) or porcine pancreatic elastase (E group) once a week during 4 weeks. C and E groups were randomized into subgroups receiving saline (SAL) or male BMDMCs (2 × 10(6), CELL) intravenously 3h after the first saline or elastase instillation. Compared to E-SAL group, E-CELL mice showed, at 5 weeks: lower mean linear intercept, neutrophil infiltration, elastolysis, collagen fiber deposition in alveolar septa and pulmonary vessel wall, lung cell apoptosis, right ventricle wall thickness and area, higher endothelial growth factor and insulin-like growth factor mRNA expressions in lung tissue, and reduced platelet-derived growth factor, transforming growth factor-β, and caspase-3 expressions. In conclusion, BMDMC therapy was effective at modulating the inflammatory and remodeling processes in the present model of elastase-induced emphysema.

Early and late effects of bone marrow-derived mononuclear cell therapy on lung and distal organs in experimental sepsis

We tested the hypothesis that bone marrow-derived mononuclear cells (BMDMCs) at an early phase of cecal ligation and puncture (CLP)-induced sepsis may have lasting effects on: (1) lung mechanics and histology, (2) the structural remodelling of lung parenchyma, (3) lung, kidney, and liver cell apoptosis, and (4) pro- and anti-inflammatory cytokines and growth factors. At day 1, BMDMC significantly reduced mortality, as well as caspase-3, interleukin (IL)-6 and IL-1β, vascular endothelial growth factor, platelet-derived growth factor, hepatocyte growth factor, and transforming growth factor-β, but increased IL-10 mRNA expression in lung tissue in septic mice contributing to endothelium and epithelium alveolar repair and improvement of lung mechanics. BMDMC also prevented the increase of apoptotic cells in lung, liver, and kidney. At day 7, these early functional and morphological effects were preserved or further improved. In conclusion, in the present model of sepsis, the beneficial effects of early administration of BMDMCs on lung and distal organs were preserved, possibly by paracrine mechanisms.

Mechanisms of cellular therapy in respiratory diseases

PURPOSE

Stem cells present a variety of clinical implications in the lungs. According to their origin, these cells can be divided into embryonic and adult stem cells; however, due to the important ethical and safety limitations that are involved in the embryonic stem cell use, most studies have chosen to focus on adult stem cell therapy. This article aims to present and clarify the recent advances in the field of stem cell biology, as well as to highlight the effects of mesenchymal stem cell (MSC) therapy in the context of acute lung injury/acute respiratory distress syndrome and chronic disorders such as lung fibrosis and chronic obstructive pulmonary disease.

METHODS

For this purpose, we performed a critical review of adult stem cell therapies, covering the main clinical and experimental studies published in Pubmed databases in the past 11 years. Different characteristics were extracted from these articles, such as: the experimental model, strain, cellular type and administration route used as well as the positive or negative effects obtained.

RESULTS

There is evidence for beneficial effects of MSC on lung development, repair, and remodeling. The engraftment in the injured lung does not occur easily, but several studies report that paracrine factors can be effective in reducing inflammation and promoting tissue repair. MSC releases several growth factors and anti-inflammatory cytokines that regulate endothelial and epithelial permeability and reduce the severity of inflammation.

CONCLUSION

A better understanding of the mechanisms that control cell division and differentiation, as well as of their paracrine effects, is required to enable the optimal use of bone marrow-derived stem cell therapy to treat human respiratory diseases.

Impact of obesity on airway and lung parenchyma remodeling in experimental chronic allergic asthma

The impact of obesity on the inflammatory process has been described in asthma, however little is known about the influence of diet-induced obesity on lung remodeling. For this purpose, 56 recently weaned A/J mice were randomly divided into 2 groups. In the C group, mice were fed a standard chow diet, while OB animals received isocaloric high-fat diet to reach 1.5 of the mean body weight of C. After 12 weeks, each group was further randomized to be sensitized and challenged with ovalbumin (OVA) or saline. Twenty-four hours after the last challenge, collagen fiber content in airways and lung parenchyma, the volume proportion of smooth muscle-specific actin in alveolar ducts and terminal bronchiole, and the number of eosinophils in bronchoalveolar lavage fluid were higher in OB-OVA than C-OVA. In conclusion, diet-induced obesity enhanced lung remodeling resulting in higher airway responsiveness in the present experimental chronic allergic asthma.