Stem cells and cell therapies in lung biology and lung diseases

The effect of multiple outgrowths from bronchial tissue explants on progenitor/stem cell number in primary bronchial epithelial cell cultures from smokers and patients with COPD

Background

Although studies suggest a deficiency in stem cell numbers in chronic airway diseases such as chronic obstructive pulmonary disease (COPD), the role of bronchial epithelial progenitor/stem (P/S) cells is not clear. The objectives of this study were to investigate expression of progenitor/stem (P/S) cell markers, cytokeratin (CK) 5, CK14 and p63 in bronchial epithelial explants and cell cultures obtained from smokers with and without COPD following multiple outgrowths, and to study this effect on bronchial epithelial cell (BEC) proliferation.

Methods

Bronchial epithelial explants were dissected from lung explants and cultured on coverslips. Confluent cultures were obtained after 3-4 weeks' (transfer, Tr1), explants were then transferred and cultured for a second (Tr2) and third (Tr3) time, respectively. At each stage, expression of CK5, CK14 and p63 in explants and BEC were determined by immunostaining. In parallel experiments, outgrowing cells from explants were counted after 4wks, and explants subsequently transferred to obtain new cultures for a further 3 times.

Results

As the transfer number advanced, CK5, CK14 and p63 expression was decreased in both explants and BEC from both smokers without COPD and patients with COPD, with a more pronounced decrease in BEC numbers in the COPD group. Total cell numbers cultured from explants were decreased with advancing outgrowth number in both groups. Smoking status and lung function parameters were correlated with reduced P/S marker expression and cell numbers.

Conclusion

Our findings suggest that the number of P/S cells in airway epithelium may play a role in the pathogenesis of COPD, as well as a role in the proliferation of airway epithelial cells, in vitro.

Regenerative and translational medicine in COPD: hype and hope

COPD is a common, preventable and usually progressive disease associated with an enhanced chronic inflammatory response in the airways and lung, generally caused by exposure to noxious particles and gases. It is a treatable disease characterised by persistent respiratory symptoms and airflow limitation due to abnormalities in the airways and/or alveoli. COPD is currently the third leading cause of death worldwide, representing a serious public health problem and a high social and economic burden. Despite significant advances, effective clinical treatments have not yet been achieved. In this scenario, cell-based therapies have emerged as potentially promising therapeutic approaches. However, there are only a few published studies of cell-based therapies in human patients with COPD and a small number of ongoing clinical trials registered on clinicaltrials.gov Despite the advances and interesting results, numerous doubts and questions remain about efficacy, mechanisms of action, culture conditions, doses, timing, route of administration and conditions related to homing and engraftment of the infused cells. This article presents the state of the art of cell-based therapy in COPD. Clinical trials that have already been completed and with published results are discussed in detail. We also discuss the questions that remain unanswered about cell-based regenerative and translational medicine for COPD.

Stanniocalcin-1 secreted by human umbilical mesenchymal stem cells regulates interleukin-10 expression via the PI3K/AKT/mTOR pathway in alveolar macrophages

Acute respiratory distress syndrome (ARDS) is a syndrome of acute respiratory failure caused by infection, trauma, shock, aspiration or drug reaction. The pathogenesis of ARDS is characterized as an unregulated inflammatory storm, which causes endothelial and epithelial layer damage, leading to alveolar fluid accumulation and pulmonary edema. Previous studies have shown the potential role of mesenchymal stem cells (MSC) in combating the inflammatory cascade by increasing the anti-inflammatory mediator interleukin-10 (IL-10). However, the involved mechanisms are unclear. Here we investigated whether a key immunomodulatory regulator, stanniocalcin-1 (STC-1), was secreted by MSC to activate phosphoinositide 3-kinase/protein kinase B (PI3K/AKT)/ mammalian target of rapamycin (mTOR) signaling pathway to increase IL-10 expression in alveolar macrophages. Lipopolysaccharide (LPS)-stimulated alveolar macrophages co-cultured with human umbilical mesenchymal stem cells (HUMSC) secreted high levels of IL-10. HUMSC co-cultured with alveolar macrophages expressed high STC-1 levels and increased PI3K, AKT and mTOR phosphorylation after LPS activation in alveolar macrophages. STC-1 knockdown in HUMSC decreased the phosphorylation of PI3K, AKT and mTOR and suppressed IL-10 expression in alveolar macrophages. Rapamycin (an mTOR inhibitor) reduced IL-10 secretion in alveolar macrophages. These results, together with our previous study and others, indicate that the PI3K/AKT/mTOR pathway is involved in the regulation of IL-10 production by STC-1 secreted by HUMSC in alveolar macrophages.

Transcriptomic Study on the Lungs of Broilers with Ascites Syndrome

Although broiler ascites syndrome (AS) has been extensively studied, its pathogenesis remains unclear. The lack of cardiopulmonary function in broilers causes relative hypoxia in the body; hence, the lung is the main target organ of AS. However, the transcriptome of AS lung tissue in broilers has not been studied. In this study, an AS model was successfully constructed, and lung tissues of three AS broilers and three healthy broilers were obtained for RNA sequencing (RNA-seq) and pathological observation. The results showed that 614 genes were up-regulated and 828 genes were down-regulated in the AS group compared with the normal group. Gene Ontology (GO) functional annotation revealed the following up-regulated genes: FABP4, APLN, EIF2AK4, HMOX1, MMP9, THBS1, TLR4, BCL2; and down-regulated genes: APELA, FGF7, WNT5A, CDK6, IL7, IL7R, APLNR. These genes have attracted much attention in cardiovascular diseases such as pulmonary hypertension. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that multiple metabolic processes were enriched, indicating abnormal lung metabolism of AS in broilers. These findings elucidate the potential genes and signal pathways in the lungs of broilers with AS and provide a potential target for studying the pathogenesis and preventing AS.

JAK2/STAT3 pathway mediates neuroprotective and pro-angiogenic treatment effects of adult human neural stem cells in middle cerebral artery occlusion stroke animal models

Mismatches between pre-clinical and clinical results of stem cell therapeutics for ischemic stroke limit their clinical applicability. To overcome these discrepancies, precise planning of pre-clinical experiments that can be translated to clinical trials and the scientific elucidation of treatment mechanisms is important. In this study, adult human neural stem cells (ahNSCs) derived from temporal lobe surgical samples were used (to avoid ethical and safety issues), and their therapeutic effects on ischemic stroke were examined using middle cerebral artery occlusion animal models. 5 × 10⁵ ahNSCs was directly injected into the lateral ventricle of contralateral brain hemispheres of immune suppressed rat stroke models at the subacute phase of stroke. Compared with the mock-treated group, ahNSCs reduced brain tissue atrophy and neurological sensorimotor and memory functional loss. Tissue analysis demonstrated that the significant therapeutic effects were mediated by the neuroprotective and pro-angiogenic activities of ahNSCs, which preserved neurons in ischemic brain areas and decreased reactive astrogliosis and microglial activation. The neuroprotective and pro-angiogenic effects of ahNSCs were validated in in vitro stroke models and were induced by paracrine factors excreted by ahNSCs. When the JAK2/STAT3 signaling pathway was inhibited by a specific inhibitor, AG490, the paracrine neuroprotective and pro-angiogenic effects of ahNSCs were reversed. This pre-clinical study that closely simulated clinical settings and provided treatment mechanisms of ahNSCs for ischemic stroke may aid the development of protocols for subsequent clinical trials of ahNSCs and the realization of clinically available stem cell therapeutics for ischemic stroke.

Therapeutic Benefits of Mesenchymal Stem Cells in Acute Respiratory Distress Syndrome: Potential Mechanisms and Challenges

Acute respiratory distress syndrome (ARDS) presents as a form of acute respiratory failure resulting from non-cardiogenic pulmonary edema due to excessive alveolocapillary permeability, which may be pulmonary or systemic in origin. In the last 3 years, the coronavirus disease 2019 pandemic has resulted in an increase in ARDS cases and highlighted the challenges associated with this syndrome, as well as the unacceptably high mortality rates and lack of effective treatments. Currently, clinical treatment remains primarily supportive, including mechanical ventilation and drug-based therapy. Mesenchymal stem cell (MSC) therapies are emerging as a promising intervention in patients with ARDS and have promising therapeutic effects and safety. The therapeutic mechanisms include modifying the immune response and assisting with tissue repair. This review provides an overview of the general properties of MSCs and outlines their role in mitigating lung injury and promoting tissue repair in ARDS. Finally, we summarize the current challenges in the study of translational MSC research and identify avenues by which the discipline may progress in the coming years.

ORIGINS: a protein network-based approach to quantify cell pluripotency from scRNA-seq data

Trajectory inference is a common application of scRNA-seq data. However, it is often necessary to previously determine the origin of the trajectories, the stem or progenitor cells. In this work, we propose a computational tool to quantify pluripotency from single cell transcriptomics data. This approach uses the protein-protein interaction (PPI) network associated with the differentiation process as a scaffold and the gene expression matrix to calculate a score that we call differentiation activity. This score reflects how active the differentiation network is in each cell. We benchmark the performance of our algorithm with two previously published tools, LandSCENT (Chen et al., 2019) and CytoTRACE (Gulati et al., 2020), for four healthy human data sets: breast, colon, hematopoietic and lung. We show that our algorithm is more efficient than LandSCENT and requires less RAM memory than the other programs. We also illustrate a complete workflow from the count matrix to trajectory inference using the breast data set.•

ORIGINS is a methodology to quantify pluripotency from scRNA-seq data implemented as a freely available R package.

•

ORIGINS uses the protein-protein interaction network associated with differentiation and the data set expression matrix to calculate a score (differentiation activity) that quantifies pluripotency for each cell.

Mesenchymal stromal cell treatment improves outcomes in children with pneumonia post-hematopoietic stem cell transplantation: a retrospective cohort study

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is a standard therapy strategy for most malignant disorders in children. However, transplant-related pneumonia remains a major therapy challenge and mesenchymal stromal cells (MSCs) are rarely reported in HSCT-related pneumonia. The aim of our study was to assess the efficacy of MSC for HSCT-related pneumonia in children.

METHODS

We retrospectively retrieved HSCT-related (severe and non-severe) pneumonia cases (aged < 18 years), which underwent MSC treatment (MSC group) or non-MSC treatment (non-MSC group) in Guangzhou Women and Children's Medical Center, from December 2017 to December 2019. We investigated outcomes of the two different treatments among severe cases and non-severe cases, respectively. The primary endpoints were differences in overall cure rate and time to cure between MSC and non-MSC groups. The secondary endpoints were 180-day overall survival and cumulative cure rate.

RESULTS

Finally, 31 severe pneumonia cases (16 in MSC group, 15 in non-MSC group) and 76 non-severe cases (31 in MSC group, 45 in non-MSC group) were enrolled in this study. Among severe pneumonia cases, overall cure rate in MSC group was significant higher than that in non-MSC group (12[75.0%] vs. 5[33.3%]; OR = 6.00, 95% CI [1.26-28.5]; p = 0.020); the time (days) to cure in MSC group was dramatically reduced compared with that in non-MSC group (36 [19-52] vs. 62 [42-81]; OR = 0.32, 95% CI [0.12-0.88]; p = 0.009); the 180-day overall survival in MSC group was better than that in non-MSC group (74.5% [45.4-89.6] vs. 33.3% [12.2-56.4]; p = 0.013). Among non-severe pneumonia cases, the time (days) to cure in MSC group was notably decreased compared with that in non-MSC group (28 [24-31] vs. 33 [26-39]; OR = 0.31, 95% CI [0.18-0.56]; p = 0.003). Compared with non-MSC group, MSC-treated patients achieved significant improvements of cumulative cure rate not only in severe pneumonia cases (p = 0.027), but also in non-severe cases (p < 0.001).

CONCLUSIONS

This study revealed that MSC treatment could contribute to improving outcomes in children with pneumonia post-HSCT, especially in severe cases. These findings suggest MSC treatment as a promising therapy for HSCT-related pneumonia in children.

Stem cells in neonatal diseases: An overview

Preterm birth and its common complications are major causes of infant mortality and long-term morbidity. Despite great advances in understanding the pathogenesis of neonatal diseases and improvements in neonatal intensive care, effective therapies for the prevention or treatment for these conditions are still lacking. Stem cell (SC) therapy is rapidly emerging as a novel therapeutic tool for several diseases of the newborn with encouraging pre-clinical results that hold promise for translation to the bedside. The utility of different types of SCs in neonatal diseases is being explored. SC therapeutic efficacy is closely associated with its secretome-conditioned media and SC-derived extracellular vesicles, and a subsequent paracrine action in response to tissue injuries. In the current review, we summarize the pre-clinical and clinical studies of SCs and its secretome in diverse preterm and term birth-related diseases, thereby providing new insights for future therapies in neonatal medicine.

Emerging importance of nanotechnology-based approaches to control the COVID-19 pandemic; focus on nanomedicine iterance in diagnosis and treatment of COVID-19 patients

The ongoing outbreak of the newly emerged coronavirus disease 2019, which has tremendously concerned global health safety, is the result of infection with severe acute respiratory syndrome of coronavirus 2 with high morbidity and mortality. Because of the coronavirus has no specific treatment, so it is necessary to early detection and produce antiviral agents and efficacious vaccines in order to prevent the contagion of coronavirus. Due to the unique properties of nanomaterials, nanotechnology appears to be a highly relevant discipline in this global emergency, providing expansive chemical functionalization to develop advanced biomedical tools. Fascinatingly, nanomedicine as a hopeful approach for the treatment and diagnosis of diseases, could efficiently help success the fight among coronavirus and host cells. In this review, we will critically discuss how nanomedicine can play an indispensable role in creating useful treatments and diagnostics for coronavirus.

Mitochondria in Focus: From Function to Therapeutic Strategies in Chronic Lung Diseases

Mitochondria are essential organelles for cell metabolism, growth, and function. Mitochondria in lung cells have important roles in regulating surfactant production, mucociliary function, mucus secretion, senescence, immunologic defense, and regeneration. Disruption in mitochondrial physiology can be the central point in several pathophysiologic pathways of chronic lung diseases such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and asthma. In this review, we summarize how mitochondria morphology, dynamics, redox signaling, mitophagy, and interaction with the endoplasmic reticulum are involved in chronic lung diseases and highlight strategies focused on mitochondrial therapy (mito-therapy) that could be tested as a potential therapeutic target for lung diseases.

Human Adipose-Derived Mesenchymal Stem Cells Ameliorate Elastase-Induced Emphysema in Mice by Mesenchymal-Epithelial Transition

Purpose

Chronic obstructive pulmonary disease (COPD) is a worldwide problem because of its high prevalence and mortality. However, there is no fundamental treatment to ameliorate their pathological change in COPD lung. Recently, adipose-derived mesenchymal stem cells (ADSCs) have attracted attention in the field of regenerative medicine to repair damaged organs. Moreover, their utility in treating respiratory diseases has been reported in some animal models. However, the detailed mechanism by which ADSCs improve chronic respiratory diseases, including COPD, remains to be elucidated. We examined whether human ADSCs (hADSCs) ameliorated elastase-induced emphysema and whether hADSCs differentiated into alveolar epithelial cells in a murine model of COPD.

Methods

Female SCID-beige mice (6 weeks old) were divided into the following four groups according to whether they received an intratracheal injection of phosphate-buffered saline or porcine pancreatic elastase, and whether they received an intravenous injection of saline or hADSCs 3 days after intratracheal injection; Control group, hADSC group, Elastase group, and Elastase-hADSC group. We evaluated the lung function, assessed histological changes, and compared gene expression between hADSCs isolated from the lung of Elastase-hADSC group and naïve hADSCs 28 days after saline or elastase administration.

Results

hADSCs improved the pathogenesis of COPD, including the mean linear intercept and forced expiratory volume, in an elastase-induced emphysema model in mice. Furthermore, hADSCs were observed in the lungs of elastase-treated mice at 25 days after administration. These cells expressed genes related to mesenchymal–epithelial transition and surface markers of alveolar epithelial cells, such as TTF-1, β-catenin, and E-cadherin.

Conclusion

hADSCs have the potential to improve the pathogenesis of COPD by differentiating into alveolar epithelial cells by mesenchymal–epithelial transition.

Diagnostic and Therapeutic Potential of Extracellular Vesicles

Extracellular vesicles (EVs) are naturally phospholipid enclosed nanovesicles released by many cells in the body. They are stable in circulation, have low immunogenicity, and act as carriers for functionally active biological molecules. They interact with target organs and bind to the receptors. Their target specificity is important to use EVs as noninvasive diagnostic and prognostic tools. EVs play a vital role in normal physiology and cellular communication. They are known to protect their cargo from degradation, which makes them important drug carriers for targeted drug delivery. Using EVs with markers and tracking their path in systemic circulation can be revolutionary in using them as diagnostic tools. We will discuss the scope of this in this paper. Although there are limitations in EVs isolation and storage, their high biocompatibility will fuel more innovations to overcome these challenges.

Clinical experience on umbilical cord mesenchymal stem cell treatment in 210 severe and critical COVID-19 cases in Turkey

Objective

Treatment for COVID-19 is still urgent need for the critically ill and severe cases. UC-MSC administration has a therapeutic benefit for severe COVID-19 patients even in the recovery period. In this paper, we aimed to present our clinical experience with UC-MSC treatment in severe and critical severe COVID-19 patients.

Methods

In this study we evaluated the clinical outcome of severe/critically severe 210 COVID-19 patients treated with UC-MSCs, 1–2 × 10⁶ per kilogram to 210 patients from 15/10/2020 until 25/04/2021.

Results

Out of 99 critically severe intubated patients we have observed good clinical progress/discharged from ICU in 52 (52.5%) patients. Where as 86 (77.5%) of 111 severe unintubated patients discharged from ICU. Intubated 47 (47.5%) patients and unintubated 25 (22.5%) patients pass away. Significantly higher survival was observed in patients who underwent UC-MSCs before intubation (OR = 1.475, 95% CI = 1.193–1.824 p < 0.001). It was observed that the SaO₂ parameter tended to improve after UC-MSC therapy compared to all groups. But SaO₂ parameter between intubated and unintubated groups was not statistically significant (p > 0.05), while in discharged cases SaO₂ parameter was statistically significant (p = 0.01). Besides, there was a statistically significant relation with intubation status, age (OR = 3.868, 95% CI = 0.574–7.152 p = 0.02) and weigh (OR = 6.768, 95% CI = 3.423–10.112 p < 0.001) thus presented an elevated risk for COVID-19. The linear regression analysis confirmed that the high weight was associated with the risk of intubation in COVID-19 (p = 0.001).

Conclusions

According to our results and from recent studies, UC-MSC treatment is safe with high potential to be used as an added therapeutic treatment for severe COVID-19 patients. Our experience showed that UC-MSC therapy may restore oxygenation and downregulate cytokine storm in patients hospitalized with severe COVID-19. We advice wider randomised studies to discover the detailed therapeutic pathophysiology of the MSCs on COVID-19 patients.

Graphical abstract

MSCs transplantation improves the damaging effects of the cytokine storm through immunomodulation and improving tissue and organ repair. Severe patients who were unintubated were in the Phase I, while critical patients who were intubated were in the Phase II. The figure is created via biorender application, (BioRender.com).

A Hybrid Injectable and Self-Healable Hydrogel System as 3D Cell Culture Scaffold

Cell therapies have great potential for the treatment of many different diseases, while the direct application of cells to the targeted location leads to limited therapeutic outcomes due to the low cell engraftment and cell survival rate. Injectable hydrogels have been developed to facilitate cell delivery; however, those currently developed hydrogel systems still face the limited cell survival rate. Here, an injectable and self-healable hydrogel is reported through the combination of hyperbranched PEG-based multi-hydrazide macro-crosslinker (HB-PEG-HDZ) and aldehyde-functionalized hyaluronic acid (HA-CHO), with gelatin added to increase the crosslinking density and cell activity. The hydrogels can be formed only in 7 s due to the relatively high content of the functional end groups. The reversible crosslinking mechanism between the hydrazide and aldehyde groups endows the hydrogel with shear-thinning and self-healing properties. The hydrogels with gelatin exhibit relatively better mechanical properties and cell activity. The hydrogels can improve the survival, attachment, and engraftment of injected cells due to the rapid sol-gel transition, which can promote an enhanced regenerative response.

Characterization of an elastase-induced emphysema model in immune-deficient rats

OBJECTIVES

Emphysema affects millions of patients worldwide. Cell transplantation and tissue engineering are promising approaches for the regeneration of gas exchange tissue in vivo. A reproducible and resource-efficient animal model with relevant pathological and physiological features is critical to assess efficacy of novel therapies. Here, we share a method for rapid development of emphysema in an adaptive immune-deficient rat with <5% mortality, which is ideal for high-throughput human cell-based experimentation.

METHODS

Porcine pancreatic elastase (PPE) was intratracheally administered to male RNU rats. Rats were monitored for 21 days after which subjects underwent lung computed tomography (CT) scans. Rats were then weighed, intubated and mechanically ventilated to measure dynamic compliance. After sacrifice, lungs were fixed, and histological sections were quantitatively assessed for emphysematous changes.

RESULTS

A single instillation of elastase was enough to produce anatomic and physiological evidence of emphysema. Weight change for doses of 16 and 32 units PPE/100 g were significantly lower than controls (P = 0.028 and P = 0.043, respectively). Compliance values for doses of 16 and 32 units PPE/100 g were significantly higher than controls (P = 0.037 and P = 0.006, respectively). Lung hyperlucency was confirmed by CT with mean Hounsfield units for a dose of 32 units PPE/100 g being significantly lower than controls (P < 0.001). The mean linear intersect for doses of 16 and 32 units PPE/100 g were significantly higher than controls (both P < 0.001). All reported P-values are one-sided.

CONCLUSIONS

We present an efficient method for emphysema development in immune-deficient rats as a tool to evaluate human biological therapeutics. Changes in dynamic compliance, histology and cross-sectional imaging recapitulate human emphysema.

Bronchioalveolar stem cells derived from mouse-induced pluripotent stem cells promote airway epithelium regeneration

Background

Bronchioalveolar stem cells (BASCs) located at the bronchioalveolar-duct junction (BADJ) are stem cells residing in alveoli and terminal bronchioles that can self-renew and differentiate into alveolar type (AT)-1 cells, AT-2 cells, club cells, and ciliated cells. Following terminal-bronchiole injury, BASCs increase in number and promote repair. However, whether BASCs can be differentiated from mouse-induced pluripotent stem cells (iPSCs) remains unreported, and the therapeutic potential of such cells is unclear. We therefore sought to differentiate BASCs from iPSCs and examine their potential for use in the treatment of epithelial injury in terminal bronchioles.

Methods

BASCs were induced using a modified protocol for differentiating mouse iPSCs into AT-2 cells. Differentiated iPSCs were intratracheally transplanted into naphthalene-treated mice. The engraftment of BASCs into the BADJ and their subsequent ability to promote repair of injury to the airway epithelium were evaluated.

Results

Flow cytometric analysis revealed that BASCs represented ~ 7% of the cells obtained. Additionally, ultrastructural analysis of these iPSC-derived BASCs via transmission electron microscopy showed that the cells containing secretory granules harboured microvilli, as well as small and immature lamellar body-like structures. When the differentiated iPSCs were intratracheally transplanted in naphthalene-induced airway epithelium injury, transplanted BASCs were found to be engrafted in the BADJ epithelium and alveolar spaces for 14 days after transplantation and to maintain the BASC phenotype. Notably, repair of the terminal-bronchiole epithelium was markedly promoted after transplantation of the differentiated iPSCs.

Conclusions

Mouse iPSCs could be differentiated in vitro into cells that display a similar phenotype to BASCs. Given that the differentiated iPSCs promoted epithelial repair in the mouse model of naphthalene-induced airway epithelium injury, this method may serve as a basis for the development of treatments for terminal-bronchiole/alveolar-region disorders.

Current and emerging therapeutic approaches to pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a progressive and fatal lung disease of multifactorial etiology. Most of the available drugs and FDA-approved therapies for treating pulmonary hypertension attempt to overcome the imbalance between vasoactive and vasodilator mediators, and restore the endothelial cell function. Traditional medications for treating PAH include the prostacyclin analogs and receptor agonists, phosphodiesterase 5 inhibitors, endothelin-receptor antagonists, and cGMP activators. While the current FDA-approved drugs showed improvements in quality of life and hemodynamic parameters, they have shown only very limited beneficial effects on survival and disease progression. None of them offers a cure against PAH, and the median survival rate remains less than three years from diagnosis. Extensive research efforts have led to the emergence of innovative therapeutic approaches in the area of PAH. In this review, we provide an overview of the current FDA-approved therapies in PAH and discuss the associated clinical trials and reported-side effects. As recent studies have led to the emergence of innovative therapeutic approaches in the area of PAH, we also focus on the latest promising therapies in preclinical studies such as stem cell-based therapies, gene transfer, and epigenetic therapies.

Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases 2017. An Official American Thoracic Society Workshop Report

The University of Vermont Larner College of Medicine, in collaboration with the National Heart, Lung, and Blood Institute (NHLBI), the Alpha-1 Foundation, the American Thoracic Society, the Cystic Fibrosis Foundation, the European Respiratory Society, the International Society for Cell & Gene Therapy, and the Pulmonary Fibrosis Foundation, convened a workshop titled "Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases" from July 24 through 27, 2017, at the University of Vermont, Burlington, Vermont. The conference objectives were to review and discuss current understanding of the following topics: 1) stem and progenitor cell biology and the role that they play in endogenous repair or as cell therapies after lung injury, 2) the emerging role of extracellular vesicles as potential therapies, 3) ex vivo bioengineering of lung and airway tissue, and 4) progress in induced pluripotent stem cell protocols for deriving lung cell types and applications in disease modeling. All of these topics are research areas in which significant and exciting progress has been made over the past few years. In addition, issues surrounding the ethics and regulation of cell therapies worldwide were discussed, with a special emphasis on combating the growing problem of unproven cell interventions being administered to patients with lung diseases. Finally, future research directions were discussed, and opportunities for both basic and translational research were identified.

Bone marrow stem cells accelerate lung maturation and prevent the LPS-induced delay of morphological and functional fetal lung development in the presence of ErbB4

ErbB4 is a regulator in lung development and disease. Prenatal infection is an important risk factor for the delay of morphologic lung development, while promoting the maturation of the surfactant system. Bone marrow-derived mesenchymal stem cells (BMSCs) have the potential to prevent lung injury. We hypothesized that BMSCs in comparison with hematopoietic control stem cells (HPSCs) minimize the lipopolysaccharide (LPS)-induced lung injury only when functional ErbB4 receptor is present. We injected LPS and/or murine green fluorescent protein-labeled BMSCs or HPSCs into the amniotic cavity of transgenic ErbB4^heart mothers at gestational day 17. Fetal lungs were analyzed 24 h later. BMSCs minimized significantly LPS-induced delay in morphological lung maturation consisting of a stereologically measured increase in mesenchyme and septal thickness and a decrease of future airspace and septal surface. This effect was more prominent and significant in the ErbB4^heart+/- lungs, suggesting that the presence of functioning ErbB4 signaling is required. BMSC also diminished the LPS induced increase in surfactant protein (Sftp)a mRNA and decrease in Sftpc mRNA is only seen if ErbB4 is present. The reduction of morphological delay of lung development and of levels of immune-modulating Sftp was more pronounced in the presence of the ErbB4 receptor. Thus, ErbB4 may be required for the protective signaling of BMSCs.

Current understanding of the therapeutic benefits of mesenchymal stem cells in acute respiratory distress syndrome

The acute respiratory distress syndrome (ARDS) is a multifaceted lung disorder in which no specific therapeutic intervention is able to effectively improve clinical outcomes. Despite an improved understanding of molecular mechanisms and advances in supportive care strategies, ARDS remains associated with high mortality, and survivors usually face long-term morbidity. In recent years, preclinical studies have provided mounting evidence of the potential of mesenchymal stem cell (MSC)-based therapies in lung diseases and critical illnesses. In several models of ARDS, MSCs have been demonstrated to induce anti-inflammatory and anti-apoptotic effects, improve epithelial and endothelial cell recovery, and enhance microbial and alveolar fluid clearance, thus resulting in improved lung and distal organ function and survival. Early-stage clinical trials have also demonstrated the safety of MSC administration in patients with ARDS, but further, large-scale investigations are required to assess the safety and efficacy profile of these therapies. In this review, we summarize the main mechanisms whereby MSCs have been shown to exert therapeutic effects in experimental ARDS. We also highlight questions that need to be further elucidated and barriers that must be overcome in order to efficiently translate MSC research into clinical practice.

Adipose-derived stem cells and adipose-derived stem cell-conditioned medium modulate in situ imbalance between collagen I- and collagen V-mediated IL-17 immune response recovering bleomycin pulmonary fibrosis

The immunogenic collagen V (Col V) and the proinflammatory cytokine interleukin (IL)-17 have been implicated in the pathogenesis of multiple autoimmune diseases. Col V is also up-regulated during adipogenesis and can stimulate adipocyte differentiation in vitro. Conditioned medium (CM) generated from adipose-derived mesenchymal stem cells (MSCs) reduces bleomycin (BLM)-induced lung injury in rats, suggesting a crucial role in situ of immunomodulatory factors secreted by MSCs in these beneficial effects. In the present work, we investigated this hypothesis, analyzing levels of plasma inflammatory mediators and inflammatory and fibrotic mediators in the lung tissue of BLM-injured rats after treatment with MSCs and CM. Pulmonary fibrosis was intratracheally induced by BLM. After 10 days, BLM animals were further randomized into subgroups receiving saline, MSCs, or CM intravenously. On days 14 and 21, the animals were euthanized, and the lungs were examined through protein expression of nitric oxide synthase (NOS), IL-17, transforming growth factor-β (TGF-β), vascular endothelial growth factor, endothelin-1, and the immunogenic Col V through histological quantitative evaluation and plasma levels of fibrinogen, Von Willebrand factor, and platelet-derived growth factor (PDGF). Rats that had been injected with MSCs and CM showed a significant increase in weight and significant improvements at 14 and 21 days after intravenous injection at both time points of analysis of plasma fibrinogen, PDGF, and Von Willebrand factor and NOS-2 expression, supporting an early anti-inflammatory action, thus reducing TGF-β and collagen I fibers. In contrast, intravenous injection of CM was able to significantly increase the deposition of Col V fibers and IL-17 on both day 14 and day 21 as compared with the amount observed in rats from the BLM group and MSC groups. In conclusion, this study reinforces previous observations on the therapeutic properties of MSCs and CM and is the first report to demonstrate the association of its actions with immunomodulatory biomarkers on lung tissue. We concluded that adipose-derived stem cells and adipose-derived stem cells-CM modulate an in situ imbalance between collagen I- and Col V-mediated IL-17 immune response, emerging as a promising therapeutic option for recovering from BLM pulmonary fibrosis.

CXCR4-Overexpressing Umbilical Cord Mesenchymal Stem Cells Enhance Protection against Radiation-Induced Lung Injury

Less quantity of transplanted mesenchymal stem cells (MSCs) influences the therapeutic effects on radiation-induced lung injury (RILI). Previous studies have demonstrated that MSCs overexpressing Chemokine (C-X-C motif) receptor 4 (CXCR4) could increase the quantity of transplanted cells to local tissues. In the present study, we conducted overexpressing CXCR4 human umbilical cord mesenchymal stem cell (HUMSC) therapy for RILI. C57BL mice received single dose of thoracic irradiation with 13 Gy of X-rays and then were administered saline, control HUMSCs, or CXCR4-overexpressing HUMSCs via tail vein. Transfection with CXCR4 enhanced the quantity of transplanted HUMSCs in the radiation-induced injured lung tissues. CXCR4-overexpressing HUMSCs not only improved histopathological changes but also decreased the radiation-induced expression of SDF-1, TGF-β1, α-SMA, and collagen I and inhibited the radiation-induced decreased expression of E-cadherin. Transplanted CXCR4-overexpressing HUMSCs also could express pro-SP-C, indicated adopting the feature of ATII. These finding suggests that CXCR4-overexpressing HUMSCs enhance the protection against RILI and may be a promising strategy for RILI treatment.

Clinical Cellular Therapeutics Accelerate Clot Formation

Clinical cellular therapeutics (CCTs) have shown preliminary efficacy in reducing inflammation after trauma, preserving cardiac function after myocardial infarction, and improving functional recovery after stroke. However, most clinically available cell lines express tissue factor (TF) which stimulates coagulation. We sought to define the degree of procoagulant activity of CCTs as related to TF expression. CCT samples from bone marrow, adipose, amniotic fluid, umbilical cord, multi-potent adult progenitor cell donors, and bone marrow mononuclear cells were tested. TF expression and phenotype were quantified using flow cytometry. Procoagulant activity of the CCTs was measured in vitro with thromboelastography and calibrated thrombogram. Fluorescence-activated cell sorting (FACS) separated samples into high- and low-TF expressing populations to isolate the contribution of TF to coagulation. A TF neutralizing antibody was incubated with samples to demonstrate loss of procoagulant function. All CCTs tested expressed procoagulant activity that correlated with expression of tissue factor. Time to clot and thrombin formation decreased with increasing TF expression. High-TF expressing cells decreased clotting time more than low-TF expressing cells when isolated from a single donor using FACS. A TF neutralizing antibody restored clotting time to control values in some, but not all, CCT samples. CCTs demonstrate wide variability in procoagulant activity related to TF expression. Time to clot and thrombin formation decreases as TF load increases and this procoagulant effect is neutralized by a TF blocking antibody. Clinical trials using CCTs are in progress and TF expression may emerge as a safety release criterion. Stem Cells Translational Medicine 2018;7:731-739.

Epithelial disruption: a new paradigm enabling human airway stem cell transplantation

BACKGROUND

Airway disease is a primary cause of morbidity and early mortality for patients with cystic fibrosis (CF). Cell transplantation therapy has proven successful for treating immune disorders and may have the potential to correct the airway disease phenotype associated with CF. Since in vivo cell delivery into unconditioned mouse airways leads to inefficient engraftment, we hypothesised that disrupting the epithelial cell layer using the agent polidocanol (PDOC) would facilitate effective transplantation of cultured stem cells in mouse nasal airways.

METHODS

In this study, 4 μL of 2% PDOC in phosphate-buffered saline was administered to the nasal airway of mice to disrupt the epithelium. At 2 or 24 h after PDOC treatment, two types of reporter gene-expressing cells were transplanted into the animals: luciferase-transduced human airway basal cells (hABC-Luc) or luciferase-transduced human amnion epithelial cells (hAEC-Luc). Bioluminescence imaging was used to assess the presence of transplanted luciferase-expressing cells over time. Data were evaluated by using two-way analysis of variance with Sidak's multiple comparison.

RESULTS

Successful transplantation was observed when hABCs were delivered 2 h after PDOC but was absent when transplantation was performed 24 h after PDOC, suggesting that a greater competitive advantage for the donor cells is present at the earlier time point. The lack of transplantation of hAECs 24 h after PDOC supports the importance of choosing the correct timing and cell type to facilitate transplantation.

CONCLUSIONS

These studies into factors that may enable successful airway transplantation of human stem cells showed that extended functioning cell presence is feasible and further supports the development of methods that alter normal epithelial layer integrity. With improvements in efficacy, manipulating the airway epithelium to make it permissive towards cell transplantation may provide another option for safe and effective correction of CF transmembrane conductance regulator function in CF airways.

Mesenchymal stem cells alleviate oxidative stress-induced mitochondrial dysfunction in the airways

BACKGROUND

Oxidative stress-induced mitochondrial dysfunction can contribute to inflammation and remodeling in patients with chronic obstructive pulmonary disease (COPD). Mesenchymal stem cells protect against lung damage in animal models of COPD. It is unknown whether these effects occur through attenuating mitochondrial dysfunction in airway cells.

OBJECTIVE

We sought to examine the effect of induced pluripotent stem cell-derived mesenchymal stem cells (iPSC-MSCs) on oxidative stress-induce mitochondrial dysfunction in human airway smooth muscle cells (ASMCs) in vitro and in mouse lungs in vivo.

METHODS

ASMCs were cocultured with iPSC-MSCs in the presence of cigarette smoke medium (CSM), and mitochondrial reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔΨm), and apoptosis were measured. Conditioned medium from iPSC-MSCs and transwell cocultures were used to detect any paracrine effects. The effect of systemic injection of iPSC-MSCs on airway inflammation and hyperresponsiveness in ozone-exposed mice was also investigated.

RESULTS

Coculture of iPSC-MSCs with ASMCs attenuated CSM-induced mitochondrial ROS, apoptosis, and ΔΨm loss in ASMCs. iPSC-MSC-conditioned medium or transwell cocultures with iPSC-MSCs reduced CSM-induced mitochondrial ROS but not ΔΨm or apoptosis in ASMCs. Mitochondrial transfer from iPSC-MSCs to ASMCs was observed after direct coculture and was enhanced by CSM. iPSC-MSCs attenuated ozone-induced mitochondrial dysfunction, airway hyperresponsiveness, and inflammation in mouse lungs.

CONCLUSION

iPSC-MSCs offered protection against oxidative stress-induced mitochondrial dysfunction in human ASMCs and in mouse lungs while reducing airway inflammation and hyperresponsiveness. These effects are, at least in part, dependent on cell-cell contact, which allows for mitochondrial transfer, and paracrine regulation. Therefore iPSC-MSCs show promise as a therapy for oxidative stress-dependent lung diseases, such as COPD.

Stem cells in lung repair and regeneration: Current applications and future promise

Lung diseases are major cause of morbidity and mortality worldwide. The progress in regenerative medicine and stem cell research in the lung are currently a fast-growing research topic that can provide solutions to these major health problems. Under normal conditions, the rate of cellular proliferation is relatively low in the lung in vivo, compared to other major organ systems. Lung injury leads to the activation of stem/progenitor cell populations that re-enter the cell cycle. Yet, little is known about stem cells in the lung, despite common thoughts that these cells could play a critical role in the repair of lung injuries. Nor do we fully understand the cellular and architectural complexity of the respiratory tract, and the diverse stem/progenitor cells that are involved in the lung repair and regeneration. In this review, we discuss the conceptual framework of lung stem/progenitor cell biology, and describe lung diseases, in which stem cell manipulations may be physiologically significant. In addition, we highlight the challenges of lung stem cell-based therapy.

Effects of mesenchymal stromal cells play a role the oxidant/antioxidant balance in a murine model of asthma

Asthma is a heterogeneous disease characterised by chronic airway inflammation. One of the most devastating consequences of this inflammatory process is the generation of reactive oxygen and nitrogen species responsible for oxidative stress. The aim of this study is to analyse the efficiency of treatment with human bone marrow-derived mesenchymal stromal cells (hMSC) in maintaining the oxidative balance in a murine model of allergic asthma by quantifying nitrotyrosine in lung tissues. After confirmation of asthma in the experimental model, samples of lung parenchyma were submitted to immunohistochemical assessment. Intravenous administration of hMSC reduced the levels of nitrotyrosine in the ASTHMA-hMSC group compared to those in the ASTHMA-SAL group. In conclusion, therapeutic administration of hMSC had a beneficial effect on oxidative stress, reducing the levels of nitrotyrosine in lung tissues in a model of allergic asthma.

Recent Updates on Treatment of Ocular Microbial Infections by Stem Cell Therapy: A Review

Ocular microbial infection has emerged as a major public health crisis during the past two decades. A variety of causative agents can cause ocular microbial infections; which are characterized by persistent and destructive inflammation of the ocular tissue; progressive visual disturbance; and may result in loss of visual function in patients if early and effective treatments are not received. The conventional therapeutic approaches to treat vision impairment and blindness resulting from microbial infections involve antimicrobial therapy to eliminate the offending pathogens or in severe cases; by surgical methods and retinal prosthesis replacing of the infected area. In cases where there is concurrent inflammation, once infection is controlled, anti-inflammatory agents are indicated to reduce ocular damage from inflammation which ensues. Despite advances in medical research; progress in the control of ocular microbial infections remains slow. The varying level of ocular tissue recovery in individuals and the incomplete visual functional restoration indicate the chief limitations of current strategies. The development of a more extensive therapy is needed to help in healing to regain vision in patients. Stem cells are multipotent stromal cells that can give rise to a vast variety of cell types following proper differentiation protocol. Stem cell therapy shows promise in reducing inflammation and repairing tissue damage on the eye caused by microbial infections by its ability to modulate immune response and promote tissue regeneration. This article reviews a selected list of common infectious agents affecting the eye; which include fungi; viruses; parasites and bacteria with the aim of discussing the current antimicrobial treatments and the associated therapeutic challenges. We also provide recent updates of the advances in stem cells studies on sepsis therapy as a suggestion of optimum treatment regime for ocular microbial infections.

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.

Intratracheal Administration of Autologous Bone Marrow-Derived Cells Ameliorates Monocrotaline-Induced Pulmonary Vessel Remodeling and Lung Inflammation in Rats

PURPOSE

Inflammation is a feature of lung injury and plays a critical role in pulmonary vascular remodeling. Bone marrow-derived cells (BMCs) have anti-inflammatory properties and favor macrophage differentiation into an alternatively activated regulatory M2 profile. We investigated the effect of autologous BMCs on monocrotaline-induced pulmonary vessel remodeling and lung inflammation in rats, by direct administration into lungs via the airway.

METHODS

BMCs were isolated and plastic-adherent cells were cultured for 3 weeks. 1 week following monocrotaline (60 mg/kg) treatment, fluorescently labeled autologous BMCs (1 × 10⁶ cells) or vehicle were administered intratracheally to male Sprague-Dawley rats. 4 weeks following monocrotaline treatment, lung pathology was evaluated.

RESULTS

Monocrotaline increased pulmonary vessel wall thickness, perivascular infiltration, alveolar septal thickening, and inflammatory cell infiltration including T lymphocytes and monocytes/macrophages in alveolar areas, and also increased mRNA expression of inflammatory-related cytokines including IL-10 in the lung. Intratracheal administration of autologous BMCs prevented pulmonary vessel wall thickening and perivascular infiltration, and increased CD163-positive M2-like macrophages in perivascular areas. BMC administration inhibited the thickening of alveolar septa and reduced monocrotaline-induced inflammatory cell infiltration in lung parenchyma compared with monocrotaline-vehicle-treated-rats. Furthermore, BMCs administration increased expression of CD163-positive cells in perivascular areas and maintained the increased mRNA expression of IL-10.

CONCLUSIONS

Intratracheal administration of autologous BMCs prevented monocrotaline-induced pulmonary vessel remodeling and lung inflammation, at least in part, through induction of alternatively activated macrophages and regulation of the local lung environment toward resolving inflammation.

Immunomodulation by Mesenchymal Stromal Cells and Their Clinical Applications

Mesenchymal stromal cells (MSCs) are multipotent progenitor cells that can be isolated and expanded from various sources. MSCs modulate the function of immune cells, including T and B lymphocytes, dendritic cells, and natural killer cells. An understanding of the interaction between MSCs and the inflammatory microenvironment will provide critical information in revealing the precise in vivo mechanisms involved in MSCs-mediated therapeutic effects, and for designing more practical protocols for the clinical use of these cells. In this review we describe the current knowledge of the unique biological properties of MSCs, the immunosuppressive effects on immune-competent cells and the paracrine role of soluble factors. A summary of the participation of MSCs in preclinical and clinical studies in treating autoimmune diseases and other diseases is described. We also discuss the current challenges of their use and their potential roles in cell therapies.

Persistence and proliferation of human mesenchymal stromal cells in the right ventricular myocardium after intracoronary injection in a large animal model of pulmonary hypertension

BACKGROUND AIMS

In this study, we demonstrate long-term persistence of human mesenchymal stromal cells (hMSCs) after intracoronary injection in a large animal model of pulmonary hypertension (PH).

METHODS

Commercially available placenta-derived hMSCs were used. Experiments were conducted on 14 female Yorkshire swine. Four animals served as controls, and 10 underwent pulmonary vein (PV) banding. After 12 ± 2 weeks, PH and PV dysfunction were confirmed by right heart catheterization and cardiac magnetic resonance imaging. hMSCs were injected in the marginal branch of the right coronary artery. Tissues were harvested 6, 9 or 24 days after infusion.

RESULTS

After 12 ± 2 weeks after PV banding, all subjects had increased mean pulmonary artery pressure (13.6 ± 3.6 versus 30.8 ± 4.5 mm Hg, P < 0.007) and a decrease in right ventricular ejection fraction from 51.7 ± 5.7% versus 30.5 ± 11.3% (P = 0.003). Intracoronary injection of hMSCs was well tolerated. Up to 24 days after hMSC injection, immunohistochemistry revealed extravascular viable human CD105⁺ mononuclear cells in the right ventricle (RV) that were Ki67⁺. This was confirmed by fluorescence in situ hybridization. CD45⁺ porcine inflammatory cells were identified, commonly seen adjacent to areas of healing microscopic infarction that likely dated to the time of the original hMSC injection. Anti-CD31 staining produced strong signals in areas of injected hMSCs. Immunohistochemistry staining for vascular cell adhesion molecule-1 showed upregulation in the clusters, where mononuclear cells were located.

CONCLUSIONS

hMSCs injected via intracoronary infusion survived up to 24 days and demonstrated proliferative capacity. hMSCs can persist long term in the RV and are potential cell source for tissue repair in RV dysfunction.

Cigarette smoke challenges bone marrow mesenchymal stem cell capacities in guinea pig

Background

Cigarette smoke (CS) is associated with lower numbers of circulating stem cells and might severely affect their mobilization, trafficking and homing. Our study was designed to demonstrate in an animal model of CS exposure whether CS affects the homing and functional capabilities of bone marrow-derived mesenchymal stem cells (BM-MSCs).

Methods

Guinea pigs (GP), exposed or sham-exposed to CS, were administered via tracheal instillation or by vascular administration with 2.5 × 10⁶ BM-MSCs obtained from CS-exposed or sham-exposed animal donors. Twenty-four hours after cell administration, animals were sacrificed and cells were visualised into lung structures by optical microscopy. BM-MSCs from 8 healthy GP and from 8 GP exposed to CS for 1 month were isolated from the femur, cultured in vitro and assessed for their proliferation, migration, senescence, differentiation potential and chemokine gene expression profile.

Results

CS-exposed animals showed greater BM-MSCs lung infiltration than sham-exposed animals regardless of route of administration. The majority of BM-MSCs localized in the alveolar septa. BM-MSCs obtained from CS-exposed animals showed lower ability to engraft and lower proliferation and migration. In vitro, BM-MSCs exposed to CS extract showed a significant reduction of proliferative, cellular differentiation and migratory potential and an increase in cellular senescence in a dose dependent manner.

Conclusion

Short-term CS exposure induces BM-MSCs dysfunction. Such dysfunction was observed in vivo, affecting the cell homing and proliferation capabilities of BM-MSCs in lungs exposed to CS and in vitro altering the rate of proliferation, senescence, differentiation and migration capacity. Additionally, CS induced a reduction in CXCL9 gene expression in the BM from CS-exposed animals underpinning a potential mechanistic action of bone marrow dysfunction.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0530-0) contains supplementary material, which is available to authorized users.

Clinical observation of umbilical cord mesenchymal stem cell treatment of severe idiopathic pulmonary fibrosis: A case report

Idiopathic pulmonary fibrosis (IPF) is a degenerative disease characterized by fibrosis. Cell therapy has been considered within the therapeutic options for IPF. In this study, we explored the potential benefits of human umbilical cord-derived mesenchymal stem cell (HUC-MSC) intravenous infusion in the management of IPF. We describe a case of a 56-year-old man with IPF who was receiving long-term oxygen therapy (LTOT). The patient underwent HUC-MSC intravenous infusion and was followed up for 12 months. Clinical and motor tests, as well as questionnaires assessing quality of life, were performed prior to and following the transplantation. At the end of 12 months, a relevant reduction of LTOT requirement was registered; improvements in terms of physical performance, quality of life, and respiratory parameters were observed in our patient. In conclusion, a program of HUC-MSC intravenous infusion appears to be beneficial to patients with IPF and may be considered as an additional therapeutic option.

Stem/progenitor cells and obstructive sleep apnea syndrome - new insights for clinical applications

Obstructive sleep apnea syndrome (OSAS) is a widespread disorder, characterized by recurrent upper airway obstruction during sleep, mostly as a result of complete or partial pharyngeal obstruction. Due to the occurrence of frequent and regular hypoxic events, patients with OSAS are at increased risk of cardiovascular disease, stroke, metabolic disorders, occupational errors, motor vehicle accidents and even death. Thus, OSAS has severe consequences and represents a significant economic burden. However, some of the consequences, as well as their costs can be reduced with appropriate detection and treatment. In this context, the recent advances that were made in stem cell biology knowledge and stem cell - based technologies hold a great promise for various medical conditions, including respiratory diseases. However, the investigation of the role of stem cells in OSAS is still recent and rather limited, requiring further studies, both in animal models and humans. The goal of this review is to summarize the current state of knowledge regarding both lung resident as well as circulating stem/progenitor cells and discuss existing controversies in the field in order to identify future research directions for clinical applications in OSAS. Also, the paper highlights the requisite for inter-institutional, multi-disciplinary research collaborations in order to achieve breakthrough results in the field.

iPSC-derived mesenchymal stem cells exert SCF-dependent recovery of cigarette smoke-induced apoptosis/proliferation imbalance in airway cells

Mesenchymal stem cells (MSCs) have emerged as a potential cell‐based therapy for pulmonary emphysema in animal models. Our previous study demonstrated that human induced pluripotent stem cell–derived MSCs (iPSC‐MSCs) were superior over bone marrow–derived MSCs (BM‐MSCs) in attenuating cigarette smoke (CS)‐induced airspace enlargement possibly through mitochondrial transfer. This study further investigated the effects of iPSC‐MSCs on inflammation, apoptosis, and proliferation in a CS‐exposed rat model and examined the effects of the secreted paracrine factor from MSCs as another possible mechanism in an in vitro model of bronchial epithelial cells. Rats were exposed to 4% CS for 1 hr daily for 56 days. At days 29 and 43, human iPSC‐MSCs or BM‐MSCs were administered intravenously. We observed significant attenuation of CS‐induced elevation of circulating 8‐isoprostane and cytokine‐induced neutrophil chemoattractant‐1 after iPSC‐MSC treatment. In line, a superior capacity of iPSC‐MSCs was also observed in ameliorating CS‐induced infiltration of macrophages and neutrophils and apoptosis/proliferation imbalance in lung sections over BM‐MSCs. In support, the conditioned medium (CdM) from iPSC‐MSCs ameliorated CS medium‐induced apoptosis/proliferation imbalance of bronchial epithelial cells in vitro. Conditioned medium from iPSC‐MSCs contained higher level of stem cell factor (SCF) than that from BM‐MSCs. Deprivation of SCF from iPSC‐MSC‐derived CdM led to a reduction in anti‐apoptotic and pro‐proliferative capacity. Taken together, our data suggest that iPSC‐MSCs may possess anti‐apoptotic/pro‐proliferative capacity in the in vivo and in vitro models of CS‐induced airway cell injury partly through paracrine secretion of SCF.

Serelaxin improves the therapeutic efficacy of RXFP1-expressing human amnion epithelial cells in experimental allergic airway disease

Current asthma therapies primarily target airway inflammation (AI) and suppress episodes of airway hyperresponsiveness (AHR) but fail to treat airway remodelling (AWR), which can develop independently of AI and contribute to irreversible airway obstruction. The present study compared the anti-remodelling and therapeutic efficacy of human bone marrow-derived mesenchymal stem cells (MSCs) to that of human amnion epithelial stem cells (AECs) in the setting of chronic allergic airways disease (AAD), in the absence or presence of an anti-fibrotic (serelaxin; RLX). Female Balb/c mice subjected to the 9-week model of ovalbumin (OVA)-induced chronic AAD, were either vehicle-treated (OVA alone) or treated with MSCs or AECs alone [intranasally (i.n.)-administered with 1×10⁶ cells once weekly], RLX alone (i.n.-administered with 0.8 mg/ml daily) or a combination of MSCs or AECs and RLX from weeks 9-11 (n=6/group). Measures of AI, AWR and AHR were then assessed. OVA alone exacerbated AI, epithelial damage/thickness, sub-epithelial extracellular matrix (ECM) and total collagen deposition, markers of collagen turnover and AHR compared with that in saline-treated counterparts (all P<0.01 compared with saline-treated controls). RLX or AECs (but not MSCs) alone normalized epithelial thickness and partially diminished the OVA-induced fibrosis and AHR by ∼40-50% (all P<0.05 compared with OVA alone). Furthermore, the combination treatments normalized epithelial thickness, measures of fibrosis and AHR to that in normal mice, and significantly decreased AI. Although AECs alone demonstrated greater protection against the AAD-induced AI, AWR and AHR, compared with that of MSCs alone, combining RLX with MSCs or AECs reversed airway fibrosis and AHR to an even greater extent.

Intratracheal Administration of Mesenchymal Stem Cells Modulates Tachykinin System, Suppresses Airway Remodeling and Reduces Airway Hyperresponsiveness in an Animal Model

BACKGROUND

The need for new options for chronic lung diseases promotes the research on stem cells for lung repair. Bone marrow-derived mesenchymal stem cells (MSCs) can modulate lung inflammation, but the data on cellular processes involved in early airway remodeling and the potential involvement of neuropeptides are scarce.

OBJECTIVES

To elucidate the mechanisms by which local administration of MSCs interferes with pathophysiological features of airway hyperresponsiveness in an animal model.

METHODS

GFP-tagged mouse MSCs were intratracheally delivered in the ovalbumin mouse model with subsequent functional tests, the analysis of cytokine levels, neuropeptide expression and histological evaluation of MSCs fate and airway pathology. Additionally, MSCs were exposed to pro-inflammatory factors in vitro.

RESULTS

Functional improvement was observed after MSC administration. Although MSCs did not adopt lung cell phenotypes, cell therapy positively affected airway remodeling reducing the hyperplastic phase of the gain in bronchial smooth muscle mass, decreasing the proliferation of epithelium in which mucus metaplasia was also lowered. Decrease of interleukin-4, interleukin-5, interleukin-13 and increase of interleukin-10 in bronchoalveolar lavage was also observed. Exposed to pro-inflammatory cytokines, MSCs upregulated indoleamine 2,3-dioxygenase. Moreover, asthma-related in vivo upregulation of pro-inflammatory neurokinin 1 and neurokinin 2 receptors was counteracted by MSCs that also determined a partial restoration of VIP, a neuropeptide with anti-inflammatory properties.

CONCLUSION

Intratracheally administered MSCs positively modulate airway remodeling, reduce inflammation and improve function, demonstrating their ability to promote tissue homeostasis in the course of experimental allergic asthma. Because of a limited tissue retention, the functional impact of MSCs may be attributed to their immunomodulatory response combined with the interference of neuropeptide system activation and tissue remodeling.

The modulation of Th2 immune pathway in the immunosuppressive effect of human umbilical cord mesenchymal stem cells in a murine asthmatic model

BACKGROUND

Asthma is a chronic airway inflammatory disease that has a high prevalence nowadays, and seeking the means of relieving asthmatic symptoms is now an issue with increased importance. While mesenchymal stem cells have been demonstrated to display immunomodulatory effects, the effect of fetus-type mesenchymal stem cells (MSCs) on asthmatic symptoms in vivo have not been reported to date.

METHODS

Female BALB/c mice at 8 weeks of age were sensitized by ovalbumin, and MSCs derived from Wharton's jelly of human umbilical cord mesenchymal stem cells (hUCMSCs) were injected into the asthmatic mice. Airway hyper-responsiveness, lung eosinophil infiltration, cytokine level in splenocyte cultures and serum immunoglobulin level were measured. Enzyme-linked immunosorbent assay was used to determine cytokine and immunoglobulin levels.

RESULTS

This current study demonstrated that hUCMSCs attenuated both lung lymphocyte and eosinophil infiltration, and significantly decreased the concentration of Th2 cytokines interleukin-5 in splenocyte cultures.

CONCLUSIONS

Human umbilical cord mesenchymal stem cells have the advantage of being easily harvested non-invasively and are capable of rapid proliferation, therefore an ideal material for stem cell-based immune therapies. The current study showed that fetal-type MSCs were able to suppress asthmatic symptoms efficiently, and its immunomodulatory effect resulted primarily from suppressing the Th2 pathway in the animal model. This study suggested that hUCMSCs could be an ideal candidate for cell-based therapies of asthma.

Immunomodulation by mesenchymal stem cells in treating human autoimmune disease-associated lung fibrosis

Background

Interstitial pneumonia in connective tissue diseases (CTD-IP) featuring inflammation and fibrosis is a leading cause of death in CTD-IP patients. The related autoimmune lung injury and disturbed self-healing process make conventional anti-inflammatory drugs ineffective. Equipped with unique immunoregulatory and regenerative properties, mesenchymal stem cells (MSCs) may represent a promising therapeutic agent in CTD-IP. In this study, we aim to define the immunopathology involved in pulmonary exacerbation during autoimmunity and to determine the potential of MSCs in correcting these disorders.

Methods

Lung and blood specimens, bronchoalveolar lavage fluid cells collected from CTD-IP patients, and human primary lung fibroblasts (HLFs) from patients pathologically diagnosed with usual interstitial pneumonia (UIP) and healthy controls were analyzed by histology, flow cytometry and molecular biology. T cell subsets involved in the process of CTD-IP were defined, while the regulatory functions of MSCs isolated from the bone marrow of normal individuals (HBMSCs) on cytotoxic T cells and CTD-UIP HLFs were investigated in vitro.

Results

Higher frequencies of cytotoxic T cells were observed in the lung and peripheral blood of CTD-IP patients, accompanied with a reduced regulatory T cell (Treg) level. CTD-UIP HLFs secreted proinflammatory cytokines in combination with upregulation of α-smooth muscle actin (α-SMA). The addition of HBMSCs in vitro increased Tregs concomitant with reduced cytotoxic T cells in an experimental cell model with dominant cytotoxic T cells, and promoted Tregs expansion in T cell subsets from patients with idiopathic pulmonary fibrosis (IPF). HBMSCs also significantly decreased proinflammatory chemokine/cytokine expression, and blocked α-SMA activation in CTD-UIP HLFs through a TGF-β1-mediated mechanism, which modulates excessive IL-6/STAT3 signaling leading to IP-10 expression. MSCs secreting a higher level of TGF-β1 appear to have an optimal anti-fibrotic efficacy in BLM-induced pulmonary fibrosis in mice.

Conclusions

Impairment of TGF-β signal transduction relevant to a persistent IL-6/STAT3 transcriptional activation contributes to reduction of Treg differentiation in CTD-IP and to myofibroblast differentiation in CTD-UIP HLFs. HBMSCs can sensitize TGF-β1 downstream signal transduction that regulates IL-6/STAT3 activation, thereby stimulating Treg expansion and facilitating anti-fibrotic IP-10 production. This may in turn block progression of lung fibrosis in autoimmunity.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0319-y) contains supplementary material, which is available to authorized users.

Hypoxic Conditioned Medium From Human Adipose-Derived Stem Cells Promotes Mouse Liver Regeneration Through JAK/STAT3 Signaling

Adipose-derived stem cells (ASCs) mainly exert their function by secreting materials that are collectively termed the secretome. Despite recent attention to the secretome as an alternative to stem cell therapy, the culture conditions for generating optimal secretome contents have not been determined. Therefore, we investigated the role of hypoxic-conditioned media (HCM) from ASCs. Normoxic-conditioned media (NCM) and HCM were obtained after culturing ASCs in 20% O2 or 1% O2 for 24 hours, respectively. Subsequently, partially hepatectomized mice were infused with saline, control medium, NCM, or HCM, and then sera and liver specimens were obtained for analyses. Hypoxia (1% O2) significantly increased mRNA expression of mediators from ASCs, including interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF). HCM infusion significantly increased the number of Ki67-positive cells in the liver (p < .05). HCM infusion significantly increased phospho-signal transducer and activator of transcription 3 (STAT3) and decreased suppressor of cytokine signaling 3 (SOCS3) expression in the liver (p < .05). To determine the role of IL-6 in liver regeneration, we then performed IL-6 RNA interference study. Conditioned media (CM) obtained from ASCs, which were transfected with either siIL-6 or siControl, were administered to partially hepatectomized mice. The siIL-6 CM groups exhibited lower liver proliferation (Ki67-positive cells) and markers of regeneration (protein expression of proliferating cell nuclear antigen, p-STAT3, HGF, and VEGF and liver weights) than the siControl CM groups (p < .05). Taken together, hypoxic preconditioning of ASCs increased expression of mediators promoting anti-inflammatory and regenerative responses. The liver regenerative effects of HCM appear to be mediated by persistent and uninhibited expression of STAT3 in the liver, which results from decreased expression of SOCS3.

SIGNIFICANCE

In this study, it was found that treatment with the medium from hypoxic-preconditioned adipose-derived stem cells (ASCs) increased the viability of hepatotoxic hepatocytes and enhance liver regeneration in partially hepatectomized mice. In addition, the researchers first revealed that the hepatoprotective effects of hypoxic-conditioned media are mediated by persistent and uninhibited expression of signal transducer and activator of transcription 3 in the liver, which result from a decreased expression of suppressor of cytokine signaling 3. Therefore, the hypoxic preconditioning of ASCs is expected to play a crucial role in regenerative medicine by optimizing the production of a highly effective secretome from ASCs.

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.

Nanotechnology for mesenchymal stem cell therapies

Mesenchymal stem cells (MSC) display great proliferative, differentiative, chemotactic, and immune-modulatory properties required to promote tissue repair. Several clinical trials based on the use of MSC are currently underway for therapeutic purposes. The aim of this article is to examine the current trends and potential impact of nanotechnology in MSC-driven regenerative medicine. Nanoparticle-based approaches are used as powerful carrier systems for the targeted delivery of bioactive molecules to ensure MSC long-term maintenance in vitro and to enhance their regenerative potential. Nanostructured materials have been developed to recapitulate the stem cell niche within a tissue and to instruct MSC toward the creation of regeneration-permissive environment. Finally, the capability of MSC to migrate toward the site of injury/inflammation has allowed for the development of diagnostic imaging systems able to monitor transplanted stem cell bio-distribution, toxicity, and therapeutic effectiveness.

Mesenchymal stem cell-conditioned media suppresses inflammation-associated overproliferation of pulmonary artery smooth muscle cells in a rat model of pulmonary hypertension

Inflammation-associated overproliferation of pulmonary artery smooth muscle cells (PASMCs) is considered to be involved in the pathogenesis of pulmonary hypertension (PH). The administration of mesenchymal stem cell-conditioned media (MSC-CM) has displayed benefits in the treatment of PH, however, the exact mechanism has yet to be elucidated. The present study aimed to determine whether MSC-CM is able to suppress overproliferation of PASMCs in PH via immunoregulation. By the administration of MSC-CM to monocrotaline (MCT)-induced PH rats, and the development of an in vitro co-culture system comprised of PASMCs and activated T cells, the therapeutic effects of MSC-CM on PH, and the changes in the expression of correlated factors, including TNF-α, calcineurin (CaN) and nuclear factor of activated T cells (NFAT), were assessed. Immunohistochemical staining results indicated that MSC-CM was able to significantly suppress the production of TNF-α in MCT-induced PH and co-culture systems; and reverse transcription-quantitative polymerase chain reaction results showed significant downregulation of the expression of CaN and NFATc2 in PASMCs (P<0.01). Furthermore, MSC-CM was able to significantly suppress CaN activity and NFATc2 activation (P<0.01), thus inhibiting the overproliferation of PASMCs. Finally, MSC-CM improved abnormalities in hemodynamics and pulmonary histology in MCT-induced PH. In conclusion, the findings of the current study suggest that administration of MSC-CM has the potential to suppress inflammation-associated overproliferation of PASMCs due to its immunosuppressive effects in PH and, thus, may serve as a beneficial therapeutic strategy.

Pretreatment with bone marrow-derived mesenchymal stromal cell-conditioned media confers pulmonary ischemic tolerance

OBJECTIVE

Mesenchymal stromal cell-based therapies have demonstrated efficacy in treating a variety of diseases. Despite the potential benefits, there are still significant hurdles that need to be overcome for clinical use. We describe a cell-free-based immunotherapy approach for inducing pulmonary ischemic tolerance by using mesenchymal stromal cell-conditioned media.

METHODS

In our well-established lung ischemia-reperfusion model, we pretreated with mesenchymal stromal cell-conditioned media 30 minutes before injury. To determine the degree of lung injury, we assessed for changes in lung vascular permeability, proinflammatory cytokines and cellular infiltrates in bronchoalveolar lavage, and histopathology. Macrophage and T-cell subsets were assessed by immunohistochemistry.

RESULTS

Pretreatment with mesenchymal stromal cell-conditioned media conferred protection against lung ischemia-reperfusion injury. This protection is characterized by a significant reduction in proinflammatory cytokines, a decrease in infiltrating inflammatory cells, and increases in M2-like macrophages and regulatory T cells.

CONCLUSIONS

Cell-free mesenchymal stromal cell-conditioned media therapy confers pulmonary ischemic tolerance. This therapy uses paracrine factors that provide beneficial protective effects by immunomodulating the inflammatory response in resident and infiltrating cell subsets.