Stem Cells for Lung Disease

Adipose stem cells in reparative goat mastitis mammary gland

Mesenchymal stem cells have been widely used in the treatment of various chronic diseases. The objective of this survey was to evaluate the therapeutic and regenerative potential of stem cells from adipose tissue (ASCs) in the milk production recovery repair of tissue injury in mastitis goats treated with antimicrobial agents prior to cell therapy. After the diagnosis of mastitis and treatment with gentamicin, eight lactating goats were selected for cellular and subsequent therapy, physical-chemical analysis of milk, ultrasonographic and histopathological examinations. The ASCs were taken from the subcutaneous fat of a young goat cultivated in vitro, marked with Qdots-655 and injected in the left mammary gland, being the right mammary gland used as the control. After 30 days the ultrasonographic and histopathological analyzes were repeated and, in the first lactation period, the physical-chemical analysis of the milk was reapeated. Before the cellular therapy, the physical-chemical quality of the milk was compromised and the ultrasonographic and histopathological analysis revealed a chronic inflammatory process and fibrous tissue. The marking of the ASCs with Qdots enabled the tracking, by fluorescence microscopy (BX41-OLYMPUS), in the mammary tissue. In the ASCs therapy, cultures showed high cellularity and characteristics favorable to preclinical studies; with the therapy the physical-chemical parameters of the milk, fat, protein, temperature and pH showed significant differences among the groups; five animals treated with ASCs reconstituted the functionality of the gland and the connective tissue reduced in quantity and inflammatory infiltrate cells. ASCs have potential for the possible regeneration of fibrous mastitis lesions in the mammary gland, however, it would be necessary to increase injection time for the histopathological analysis, since the reconstitution of the glandular acini within the assessed period was not finalized. ASCs can be used to reestablish milk production in goat with chronic mastitis repair mammary lesions, with potential to be a promising clinical alternative for animal rehabilitation for productivity.

Stem cells therapy: a review on approaches that can be used for treatment of respiratory failures in sulfur mustard-injured patients

Sulfur mustard (SM) is a toxic agent which causes severe abnormalities in an airway system such as necrosis and inflammation, oxidative stress, chronic bronchitis, shortness of breath, and chronic obstructive pulmonary disease. Although possible mechanisms of SM toxicity have been extensively considered, there is still need to find an appropriate clinical treatment to decrease chronic lung injuries caused by SM. Due to extensive progresses and achievement in tissue repairing through stem cells therapy, the importance of cell therapy for the treatment of lung injuries has been increased. However, several factors such as types of stem cells, necessary conditions for growth and proliferation of stem cells, and their homing into the target tissues are considered as the most important problems in this issue. Mesenchymal stem cells (MSCs) are a class of multipotent stem cells with proliferative and self-renewal capacity which are able to differentiate into different cell lines such as lung epithelial cells. They have a potential repairing and immune modulatory properties which make them as a good candidate for the regeneration of bronchioles tract in SM-exposed patients. Unlike chemical drugs, the differentiation and high-level safety properties of MSCs can be considered as a new strategy for the treatment of SM-injured patients with pulmonary complications. This review aims to consider the therapeutic effects of MSCs in the treatment of SM-induced pulmonary injuries in both animals and humans.

Impact of bone marrow-derived mesenchymal stem cells on remodeling the lung injury induced by lipopolysaccharides in mice

AIM

This study evaluated the potential of bone marrow derived mesenchymal stem cells (MSCs) to regulate cytokines and remodel the lung induced by lipopolysaccharide (LPS; O-antigen).

MATERIALS & METHODS

A group of mice (n = 21) was inoculated intraperitoneally with one dose 0.1 ml containing 0.025 mg LPS/mouse, and another treated intravenously with one dose of labeling bone marrow derived MSCs at 7.5 × 10⁵ cell/mouse 4 h after LPS injection. All animals were sacrificed on the 1st, 7th and 14th days post-injection.

RESULTS

MSCs increased the level of IL-10 with suppression of TNF-α, decrease of collagen fibers and renewal of alveolar type I cells, together with lung tissue remodeling.

CONCLUSION

MSCs were shown to modulate inflammatory cytokines (TNF-α and IL-10) and to differentiate into alveolar type I cells, which prevented fibrosis in lung tissue from LPS-treated mice.

Stem Cells and Lung Regeneration

Background:Tissues such as the lung, liver, and pancreas that have a low steady-state cell turnover yet can respond robustly after injury to replace damaged cells. The airway epithelium is exposed to inhaled particles and pathogens that may lead to the development of a many infectious and inflammatory respiratory diseases. Lung transplantation is an accepted modality of treatment for end-stage lung diseases. Since the early 1990 s, more than 26,000 lung transplants have been performed at centers worldwide. However, the availability of donor tissues and organs is limited, which presents a serious limitation for widespread transplantation surgery. The appearance of bioengineered lung and tracheal tissue transplants is considered a promising alternative to the classical transplantation of donor organ/tissue. Stem cells therapy arises as a new therapeutic approach, with a wide application potential.

Comparison of TGF-β1 and NO production by mesenchymal stem cells isolated from murine lung and adipose tissues

CONTEXT

Mesenchymal stem cells (MSCs) are cell sources for tissues regeneration. By secretion of soluble factors including transforming growth factor-β (TGF-β1) and nitric oxide (NO), MSCs are also able to regulate the immune system. MSCs have been disclosed in lung and adipose tissues with insufficient comparison between the tissues.

OBJECTIVES

In this study, specific differentiation and the expression of surface antigens as well as TGF-β1 and NO productive levels were compared in murine lung-derived MSCs (LMSCs) and adipose tissue-derived MSCs (ADMSCs).

MATERIALS AND METHODS

MSCs were isolated from murine lung and adipose tissues and cultured. Both cell populations were characterized using multilineage potential and the expression of surface antigenic proteins, CD73, CD105, CD34, CD45, and CD11b. Finally, levels of TGF-β1 and NO were evaluated and compared in ADMSCs and LMSCs.

RESULTS

Expression of CD73 and CD105; lack of the expression of CD34, CD45, and CD11b markers; as well as adipocyte and osteocyte differentiations were detected in both adult stem cells. No significant difference was found in TGF-β1 and NO production between two stem cell populations.

CONCLUSION

Our data showed that LMSCs and ADMSCs have comparable phenotype and TGF-β1 and NO production.

Quantitative evaluation of the transplanted lin(-) hematopoietic cell migration kinetics

Stem cells take part in organogenesis, cell maturation and injury repair. The migration is necessary for each of these functions to occur. The aim of this study was to investigate the kinetics of transplanted hematopoietic lin(-) cell population (which consists mainly of the stem and progenitor cells) in BALB/c mouse contact hypersensitivity model and quantify the migration to the site of inflammation in the affected foot and other healthy organs. Quantitative analysis was carried out with the real-time polymerase chain reaction method. Spleen, kidney, bone marrow, lung, liver, damaged and healthy foot tissue samples at different time points were collected for analysis. The quantitative data normalization was performed according to the comparative quantification method. The analysis of foot samples shows the significant migration of transplanted cells to the recipient mice affected foot. The quantity was more than 1000 times higher, as compared with that of the untreated foot. Due to the inflammation, the number of donor origin cells migrating to the lungs, liver, spleen and bone marrow was found to be decreased. Our data shows that transplanted cells selectively migrated into the inflammation areas of the foot edema. Also, the inflammation caused a secondary migration in ectopic spleen of hematopoietic stem cell niches and re-homing from the spleen to the bone marrow took place.

Clinical potentials of human pluripotent stem cells in lung diseases

Lung possesses very limited regenerative capacity. Failure to maintain homeostasis of lung epithelial cell populations has been implicated in the development of many life-threatening pulmonary diseases leading to substantial morbidity and mortality worldwide, and currently there is no known cure for these end-stage pulmonary diseases. Embryonic stem cells (ESCs) and somatic cell-derived induced pluripotent stem cells (iPSCs) possess unlimited self-renewal capacity and great potential to differentiate to various cell types of three embryonic germ layers (ectodermal, mesodermal, and endodermal). Therapeutic use of human ESC/iPSC-derived lung progenitor cells for regeneration of injured or diseased lungs will have an enormous clinical impact. This article provides an overview of recent advances in research on pluripotent stem cells in lung tissue regeneration and discusses technical challenges that must be overcome for their clinical applications in the future.

Intravenous and intratracheal mesenchymal stromal cell injection in a mouse model of pulmonary emphysema

The aim of this study was to characterize the evolution of lung function and -structure in elastase-induced emphysema in adult mice and the effect of mesenchymal stromal cell (MSC) administration on these parameters. Adult mice were treated with intratracheal (4.8 units/100 g bodyweight) elastase to induce emphysema. MSCs were administered intratracheally or intravenously, before or after elastase injection. Lung function measurements, histological and morphometric analysis of lung tissue were performed at 3 weeks, 5 and 10 months after elastase and at 19, 20 and 21 days following MSC administration. Elastase-treated mice showed increased dynamic compliance and total lung capacity, and reduced tissue-specific elastance and forced expiratory flows at 3 weeks after elastase, which persisted during 10 months follow-up. Histology showed heterogeneous alveolar destruction which also persisted during long-term follow-up. Jugular vein injection of MSCs before elastase inhibited deterioration of lung function but had no effects on histology. Intratracheal MSC treatment did not modify lung function or histology. In conclusion, elastase-treated mice displayed persistent characteristics of pulmonary emphysema. Jugular vein injection of MSCs prior to elastase reduced deterioration of lung function. Intratracheal MSC treatment had no effect on lung function or histology.

Suppressive effect of compact bone-derived mesenchymal stem cells on chronic airway remodeling in murine model of asthma

New therapeutic strategies are needed in the treatment of asthma besides vaccines and pharmacotherapies. For the development of novel therapies, the use of mesenchymal stem cells (MSCs) is a promising approach in regenerative medicine. Delivery of compact bone (CB) derived MSCs to the injured lungs is an alternative treatment strategy for chronic asthma. In this study, we aimed to isolate highly enriched population of MSCs from mouse CB with regenerative capacity, and to investigate the impact of these cells in airway remodeling and inflammation in experimental ovalbumin-induced mouse model of chronic asthma. mCB-MSCs were isolated, characterized, labeled with GFP and then transferred into mice with chronic asthma developed by ovalbumin (OVA) provocation. Histopathological changes including basement membrane, epithelium, subepithelial smooth thickness and goblet cell hyperplasia, and MSCs migration to lung tissues were evaluated. These histopathological alterations were increased in ovalbumin-treated mice compared to PBS group (P<0.001). Intravenous administration of mCB-MSC significantly reduced these histopathological changes in both distal and proximal airways (P<0.001). We showed that GFP-labeled MSCs were located in the lungs of OVA group 2weeks after intravenous induction. mCB-MSCs also significantly promoted Treg response in ovalbumin-treated mice (OVA+MSC group) (P<0.037). Our studies revealed that mCB-MSCs migrated to lung tissue and suppressed histopathological changes in murine model of asthma. The results reported here provided evidence that mCB-MSCs may be an alternative strategy for the treatment of remodeling and inflammation associated with chronic asthma.

Intratracheal administration of umbilical cord blood-derived mesenchymal stem cells in a patient with acute respiratory distress syndrome

Umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) have been introduced as a possible therapy in acute lung injury and acute respiratory distress syndrome (ARDS). This case history is reported of a 59-yr-old man who was treated with MSCs in the course of ARDS and subsequent pulmonary fibrosis. He received a long period of mechanical ventilation and weaning proved difficult. On hospital day 114, he underwent the intratracheal administration of UCB-derived MSCs at a dose of 1 × 10(6)/kg. After cell infusion, an immediate improvement was shown in his mental status, his lung compliance (from 22.7 mL/cmH2O to 27.9 mL/cmH2O), PaO2/FiO2 ratio (from 191 mmHg to 334 mmHg) and his chest radiography over the course of three days. Even though he finally died of repeated pulmonary infection, our current findings suggest the possibility of using MSCs therapy in an ARDS patient. It is the first clinical case of UCB-derived MSCs therapy ever reported.

Cell therapy with bone marrow mononuclear cells in elastase-induced pulmonary emphysema

Emphysema is characterized by destruction of alveolar walls with loss of gas exchange surface and consequent progressive dyspnea. This study aimed to evaluate the efficiency of cell therapy with bone marrow mononuclear cells (BMMC) in an animal model of elastase-induced pulmonary emphysema. Emphysema was induced in C57Bl/J6 female mice by intranasal instillation of elastase. After 21 days, the mice received bone marrow mononuclear cells from EGFP male mice with C57Bl/J6 background. The groups were assessed by comparison and statistically significant differences (p < 0.05) were observed among the groups treated with BMMC and evaluated after 7, 14 and 21 days. Analysis of the mean linear intercept (Lm) values for the different groups allowed to observe that the group treated with BMMC and evaluated after 21 days showed the most significant result. The group that received no treatment showed a statistically significant difference when compared to other groups, except the group treated and evaluated after 21 days, evidencing the efficacy of cell therapy with BMMC in pulmonary emphysema.

Mobilization of endothelial progenitor cells from bone marrow is impaired in a piglet model of acute respiratory distress syndrome

OBJECTIVES

To characterize the endothelial progenitor cell mobilization in the models of moderate and severe lung injury, we hypothesized that there were differences in endothelial progenitor cell levels and mobilizing cytokines between moderate and severe lung injury.

DESIGN

Prospective, randomized, and controlled experimental study.

SETTING

University research laboratory center.

SUBJECTS

Fifteen healthy piglets.

INTERVENTIONS

Piglets were randomly allocated to control, moderate lung injury (acute lung injury), and severe lung injury (acute respiratory distress syndrome) groups. Lung injury was established by intravenous infusion of oleic acid. Animals were mechanically ventilated for 24-48 hours, and then animals were weaned from ventilation and cared for until day 7.

MEASUREMENTS AND MAIN RESULTS

Endothelial progenitor cells were quantified by flow cytometry. After 24 hours, the number of endothelial progenitor cells in peripheral blood increased in the acute lung injury group but was not altered in the acute respiratory distress syndrome group compared to the control group. The number of CD34KDR, KDRCD133, and CD34KDRCD133 cells was higher in the acute lung injury group than in the acute respiratory distress syndrome group. In bone marrow, the number of CD34KDR and KDRCD133 cells was greater in acute respiratory distress syndrome animals but not altered in acute lung injury animals at 24 hours. Furthermore, plasma stromal cell-derived factor-1 and vascular endothelial growth factor concentrations were higher in acute lung injury than in acute respiratory distress syndrome at 24 hours. Matrix metalloproteinase-9 and soluble kit ligand levels in bone marrow were reduced in acute respiratory distress syndrome compared with acute lung injury. Lung CD34, KDR, and lung stromal cell-derived factor-1 messenger RNA expression were higher in the acute lung injury group than in the acute respiratory distress syndrome group. Furthermore, the expression of CD34, KDR, and CD133 messenger RNA in lung tissue was correlated with stromal cell-derived factor-1 in the lung.

CONCLUSIONS

There was a rapid release of endothelial progenitor cells from bone marrow into circulation in moderate acute lung injury, and endothelial progenitor cell mobilization was impaired in acute respiratory distress syndrome.

Diagnosis and management of miliary tuberculosis: current state and future perspectives

Tuberculosis (TB) remains one of the most important causes of death from an infectious disease, and it poses formidable challenges to global health at the public health, scientific, and political level. Miliary TB is a potentially fatal form of TB that results from massive lymphohematogenous dissemination of Mycobacterium tuberculosis bacilli. The epidemiology of miliary TB has been altered by the emergence of the human immunodeficiency virus (HIV) infection and widespread use of immunosuppressive drugs. Diagnosis of miliary TB is a challenge that can perplex even the most experienced clinicians. There are nonspecific clinical symptoms, and the chest radiographs do not always reveal classical miliary changes. Atypical presentations like cryptic miliary TB and acute respiratory distress syndrome often lead to delayed diagnosis. High-resolution computed tomography (HRCT) is relatively more sensitive and shows randomly distributed miliary nodules. In extrapulmonary locations, ultrasonography, CT, and magnetic resonance imaging are useful in discerning the extent of organ involvement by lesions of miliary TB. Recently, positron-emission tomographic CT has been investigated as a promising tool for evaluation of suspected TB. Fundus examination for choroid tubercles, histopathological examination of tissue biopsy specimens, and rapid culture methods for isolation of M. tuberculosis in sputum, body fluids, and other body tissues aid in confirming the diagnosis. Several novel diagnostic tests have recently become available for detecting active TB disease, screening for latent M. tuberculosis infection, and identifying drug-resistant strains of M. tuberculosis. However, progress toward a robust point-of-care test has been limited, and novel biomarker discovery remains challenging. A high index of clinical suspicion and early diagnosis and timely institution of antituberculosis treatment can be lifesaving. Response to first-line antituberculosis drugs is good, but drug-induced hepatotoxicity and drug-drug interactions in HIV/TB coinfected patients create significant problems during treatment. Data available from randomized controlled trials are insufficient to define the optimum regimen and duration of treatment in patients with drug-sensitive as well as drug-resistant miliary TB, including those with HIV/AIDS, and the role of adjunctive corticosteroid treatment has not been properly studied. Research is going on worldwide in an attempt to provide a more effective vaccine than bacille Calmette-Guérin. This review highlights the epidemiology and clinical manifestation of miliary TB, challenges, recent advances, needs, and opportunities related to TB diagnostics and treatment.

Knowledge translation: airway epithelial cell migration and respiratory diseases

Airway epithelial cell migration is essential for lung development and growth, as well as the maintenance of respiratory tissue integrity. This vital cellular process is also important for the repair and regeneration of damaged airway epithelium. More importantly, several lung diseases characterized by aberrant tissue remodeling result from the improper repair of damaged respiratory tissue. Epithelial cell migration relies upon extracellular matrix molecules and is further regulated by numerous local, neuronal, and hormonal factors. Under inflammatory conditions, cell migration can also be stimulated by certain cytokines and chemokines. Many well-known environmental factors involved in the pathogenesis of chronic lung diseases (e.g., cigarette smoking, air pollution, alcohol intake, inflammation, viral and bacterial infections) can inhibit airway epithelial cell migration. Further investigation of cellular and molecular mechanisms of cell migration with advanced techniques may provide knowledge that is relevant to physiological and pathological conditions. These studies may eventually lead to the development of therapeutic interventions to improve lung repair and regeneration and to prevent aberrant remodeling in the lung.

Mesenchymal stem cells ameliorate the histopathological changes in a murine model of chronic asthma

Asthma therapies are effective in reducing inflammation but airway remodeling is poorly responsive to these agents. New therapeutic options that have fewer side effects and reverse chronic changes in the lungs are essential. Mesenchymal stem cells (MSCs) are promising for the development of novel therapies in regenerative medicine. This study aimed to examine the efficacy of MSCs on lung histopathology in a murine model of chronic asthma. BALB/c mice were divided into four groups: Group 1 (control group, n=6), Group 2 (ovalbumin induced asthma only, n=10), Group 3 (ovalbumin induced asthma + MSCs, n=10), and Group 4 (MSCs only, n=10). Histological findings (basement membrane, epithelium, subepithelial smooth muscle thickness, numbers of goblet and mast cells) of the airways and MSC migration were evaluated by light, electron, and confocal microscopes. In Group 3, all early histopathological changes except epithelial thickness and all of the chronic changes were significantly ameliorated when compared with Group 2. Evaluation with confocal microscopy showed that no noteworthy amount of MSCs were present in the lung tissues of Group 4 while significant amount of MSCs was detected in Group 3. Serum NO levels in Group 3, were significantly lower than Group 2. The results of this study revealed that MSCs migrated to lung tissue and ameliorated bronchial asthma in murine model. Further studies are needed to evaluate the efficacy of MSCs for the treatment of asthma.

Cell therapy for fibrotic interstitial pulmonary disease: experimental study

Parte superior do formulário Digite um texto ou endereço de um site ou traduza um documento. The aim of this study is to evaluate the histological changes in lung parenchyma of pigs affected by interstitial lung disease induced after the infusion of bone marrow mononuclear cells (BMMCs). Ten female swines were submitted to pulmonary fibrosis induced by a single dose of intratracheal bleomicine sulfate. Animals were arranged into two groups: Group 1: induced-disease control and Group 2: cell therapy using BMMCs. Both groups were clinically evaluated for 180 days. High-resolution computed tomography (HRCT) was performed at 90 and 180 days. BMMC sampling was performed in cell therapy group at 90 days. Euthanasia was performed, and samples were collected for histology and immunohistochemistry. The 90-days HRCT demonstrated typical interstitial lesions in pulmonary parenchyma similarly to human disease. The 180-days HRCT in Group 1 demonstrated advanced stages of the disease when compared with Group 2. Immunohistochemistry analysis suggests the presence of pre-existent vessels and neoformed vessels as well as predominant young cells in the injured parenchyma of Group 2. Immunohistochemistry analysis suggests that cell therapy would promote a reconstructive response. Histology and HRCT analysis suggest a positive application of swine as a model for a bleomicine inducing of fibrotic interstitial pulmonary disease.

Activation of the WNT/β-catenin pathway attenuates experimental emphysema

RATIONALE

Chronic obstructive pulmonary disease (COPD) is a devastating disease, for which no causal therapy is available.

OBJECTIVES

To characterize WNT/β-catenin signaling in COPD in humans and elucidate its potential role as a preventive and therapeutic target in experimental emphysema in mice.

METHODS

The expression, localization, and activity of WNT/β-catenin signaling was assessed in 12 COPD and 12 transplant donor samples using quantitative reverse transcriptase polymerase chain reaction, immunohistochemistry, and Western blotting. The role of WNT/β-catenin signaling was assessed in elastase- and cigarette smoke-induced emphysema and therapeutic modulation thereof in elastase-induced emphysema in TOPGAL reporter and wild-type mice in vivo.

MEASUREMENTS AND MAIN RESULTS

No differences in the mRNA expression profile of the main WNT/β-catenin signaling components were observed comparing COPD and donor lung homogenates. Immunohistochemical analysis revealed reduced numbers of nuclear β-catenin-positive alveolar epithelial cells in COPD. Similarly, WNT/β-catenin signaling was down-regulated in both experimental emphysema models. Preventive and therapeutic, WNT/β-catenin activation by lithium chloride attenuated experimental emphysema, as assessed by decreased airspace enlargement, improved lung function, reduced collagen content, and elevated expression of alveolar epithelial cell markers.

CONCLUSIONS

Decreased WNT/β-catenin signaling is involved in parenchymal tissue destruction and impaired repair capacity in emphysema. These data indicate a crucial role of WNT/β-catenin signaling in lung repair mechanisms in vivo, and highlight WNT/β-catenin activation as a future therapeutic approach for emphysema.

Mobilization of endothelial progenitor cells by intravenous cyclophosphamide in patients with systemic sclerosis

OBJECTIVE

To evaluate the effects of i.v. CYC on the number of circulating endothelial progenitor cells (EPCs) in patients with SSc, and the potential association of the EPC response with CYC's effect for treating interstitial lung disease (ILD).

METHODS

This open-label, prospective study involved 12 patients with SSc and alveolitis (CYC group). All patients received six courses of i.v. CYC (0.5 g/m2) at 4-week intervals in combination with low-dose prednisolone. Ten patients were followed for 24 months. Seven SSc patients treated with low-dose prednisolone alone were used as a control for the EPC measurement (control group). Five patients with non-SSc CTD who received i.v. CYC and prednisolone also served as disease controls. EPCs were quantified by the partial enrichment of CD34+ cells followed by three-colour flow cytometry. The circulating levels of vascular injury markers were measured by immunoassay.

RESULTS

The EPC count was significantly increased at 2 weeks after treatment in the CYC group (P=0.02), but not in the control group, while CYC increased EPC count in all disease controls. The SSc patients in the CYC group were divided into five EPC responders and seven EPC non-responders. Circulating vascular injury markers were reduced in the responders, but not in the non-responders. During the 24-month follow-up, 3 of 10 patients developed end-stage lung disease, and all of them were EPC non-responders.

CONCLUSION

A low-dose i.v. CYC induces EPC mobilization, which may contribute to the efficacy for treating SSc-associated ILD.

Mesenchymal stem cell therapy for the treatment of chronic obstructive pulmonary disease

Recent studies have revealed that adult stem cells such as bone marrow-derived cells contribute to lung tissue regeneration and protection, and thus administration of exogenous stem/progenitor cells may be a potent next-generation therapy for COPD. Pathogenesis of COPD is characterized by an upregulation of inflammatory processes leading to irreversible events such as apoptosis of epithelial cells, proteolysis of the terminal air-space and lung extracellular matrix components. The available pharmacological treatments are essentially symptomatic, therefore, there is a need to develop more effective therapeutic strategies. It has been previously demonstrated that transplanted MSC home to the lung in response to lung injury and adopt phenotypes of alveolar epithelial cells, endothelial cells, fibroblasts and bronchial epithelial cells. However, engraftment and differentiation are now felt to be rare occurrences and other mechanisms might be involved and play a more important role. Importantly, MSCs protect lung tissue through suppression of proinflammatory cytokines, and through triggering production of reparative growth factors. Accordingly, it is not clear if and how these cells will be able to repair, to slow or to prevent the disease. This article reviews recent advances in regenerative medicine in COPD and highlights that their potential application although promising and very attractive, are still a far away opinion.

Circulating CD34(+) cells are elevated in neonates with respiratory distress syndrome

OBJECTIVES

The objective of the paper was to determine whether circulating stem-progenitor cells were elevated along with its mobilizing cytokines in neonatal respiratory distress syndrome (RDS).

SUBJECTS AND METHODS

Circulating CD34(+) cells were identified by flow cytometry in 41 RDS in comparison with 20 preterm and 14 term controls without diffuse lung diseases. Plasma concentrations of vascular endothelial growth factor, stromal cell-derived factor-1 (SDF-1) and granulocyte-macrophage colony-stimulating factor were determined by immunochemical assays.

RESULTS

The number of CD34(+) cells was significantly higher in RDS [25(6-174) cells/microl] than in the preterm controls [15(1-100) cells/microl, P < 0.05]. RDS survivors had higher level of CD34(+) cells than non-survivors (P < 0.05), and low CD34(+) cell level in RDS was correlated with prolonged duration of ventilation (r = -0.396, P < 0.05). Likewise, the CD34(+) cell level was inversely associated with Score for Neonatal Acute Physiology Perinatal Extension II (r = -0.473, P < 0.01) in RDS. Plasma SDF-1 concentration was significantly higher in RDS than in the preterm controls (P < 0.01), and was correlated with the level of CD34(+) cells (r = 0.305, P < 0.01).

CONCLUSIONS

The level of circulating CD34(+) cells was elevated in RDS along with an increase of plasma SDF-1, suggesting CD34(+) cells might be involved in reparation of neonatal lung injury.

Tracheal replacement with cryopreserved allogenic aorta

BACKGROUND

Radical resection of primary tracheal tumors may be challenging when more than one-half of the tracheal length is concerned. The present study evaluated the use of cryopreserved aortic allografts (CAAs) to replace long tracheal segments.

METHODS

Sixteen adult minipigs underwent tracheal replacement with a CAA. A silicone stent was used to splint the CAA for the first 12 months. Animals were followed-up using bronchoscopic evaluation and killed at predetermined times, for a period up to 18 months long.

RESULTS

Intense inflammation and progressive disappearance of typical histologic structures of the aorta were seen within the first 3 months. All animals studied for more than 3 months showed progressive transformation of the graft into a chimerical conduit sharing aortic and tracheal histologic patterns (eg, islands of disorganized elastic fibers/mature respiratory ciliated epithelium, respiratory glands, islets of cartilage). Stent removal was attempted after 12 months in 10 animals, and critical tracheal stenosis was found in six animals and moderate asymptomatic stenosis in four. Clinical course in these latter animals was uneventful until they were killed at 15 to 18 months. In situ hybridization showed that collagen2a1 mRNA was expressed in the cartilage islets at 1 year. Polymerase chain reaction analysis of the SRY gene demonstrated that the newly formed cartilage cells derived from the host.

CONCLUSIONS

CAA may be considered as a valuable tracheal substitute for patients with extensive tracheal tumors. Prolonged stenting will be probably mandatory for the clinical application of the procedure in humans.

Stem cell therapy: the great promise in lung disease

Lung injuries are leading causes of morbidity and mortality worldwide. Pulmonary diseases such as asthma or chronic obstructive pulmonary disease characterized by loss of lung elasticity, small airway tethers, and luminal obstruction with inflammatory mucoid secretions, or idiopathic pulmonary fibrosis characterized by excessive matrix deposition and destruction of the normal lung architecture, have essentially symptomatic treatments and their management is costly to the health care system.Regeneration of tissue by stem cells from endogenous, exogenous, and even genetically modified cells is a promising novel therapy. The use of adult stem cells to help with lung regeneration and repair could be a newer technology in clinical and regenerative medicine. In fact, different studies have shown that bone marrow progenitor cells contribute to repair and remodeling of lung in animal models of progressive pulmonary hypertension.Therefore, lung stem cell biology may provide novel approaches to therapy and could represent a great promise for the future of molecular medicine. In fact, several diseases can be slowed or even blocked by stem cell transplantation.

Adult stem cell plasticity: neoblast repopulation in non-lethally irradiated planarians

Planarians are a model system for studying adult stem cells, as they possess the neoblasts, a population of pluripotent adult stem cells able to give rise to both somatic and germ cells. Although over the last years several efforts have been made to shed light on neoblast biology, only recent evidence indicate that this population of cells is heterogeneous. In this study we irradiated planarians with different non-lethal X-ray doses (1-5 Gy) and we identified subpopulations of neoblasts with diverse levels of tolerance to X-rays. We demonstrated that a dramatic reduction of neoblasts occurred soon after non-lethal irradiations and that de-novo proliferation of some radioresistant cells re-established the primary neoblast number. In particular, a strong proliferation activity occurred at the ventral side of irradiated animals close to the nervous system. The produced cells migrated towards the dorsal parenchyma and, together with some dorsal radioresistant cells, reconstituted the entire neoblast population demonstrating the extreme plasticity of this adult stem cell system.

The involvement of pro-inflammatory cytokines in nephrogenic systemic fibrosis - a mechanistic hypothesis based on preclinical results from a rat model treated with gadodiamide

The evidence for the potential involvement of gadolinium-based contrast agents (GBCAs) in the pathomechanism of nephrogenic systemic fibrosis (NSF), a rare but serious disease occurring in patients with severe or end-stage renal failure, has grown due to recent epidemiological and preclinical research. Nevertheless there is still uncertainty with regard to the prevailing patho-physiological processes that may lead to NSF. To examine the potential mechanism of the fibrotic skin changes we applied a recently published rat model of NSF for investigations into serum markers for inflammation. For this purpose male Wistar rats were treated either once, three, or eight times with a daily intravenous injection of 2.5 mmol/kg gadodiamide, the drug substance of the magnetic resonance imaging (MRI) agent Omniscan. Clinical observations, hematology, clinical pathology, histopathology including electron microscopy and gadolinium (Gd) determination in serum, skin, femur and liver tissue, and a multiplexed analysis of 70 protein serum markers were performed. Gd was detectable in the skin, femur, and liver of the gadodiamide-treated rats 6h after the first administration. Macroscopic skin changes, appearing as reddening and early scab formation, were observed in one animal after the third daily administration and affected all animals after 8 daily administrations. Microscopy revealed dermal infiltrations after three administrations, progressing towards inflammatory lesions, ulcerations and crusts. Among the investigated serum marker panel 13 cytokines were significantly (p<0.01) elevated 6 h after the first injection, and eight stayed elevated over all time points: the monocyte chemotactic proteins MCP-1 and MCP-3, the macrophage inflammatory proteins MIP-1beta and MIP-2, the tumor necrosis factor TNF-alpha, the extracellular matrix regulator tissue inhibitor of metalloproteinase type 1 (TIMP-1), the vascular epithelial growth factor (VEGF) and osteopontin. The latter cytokine is of particular interest, since this matrix cellular glycoprotein is involved in the regulation of dystrophic calcification but also plays a role as a chemoattractant for dendritic cells, macrophages and T-lymphocytes, which in turn activate inflammatory pathways. Reflecting the physiological role of osteopontin, we hypothesize that Gd release from the GBCA-complex leads to the formation of insoluble Gd-deposits subsequently eliciting a physiological response similar to that seen during dystrophic calcification, i.e. an up-regulation of osteopontin and chemoattractant cytokines. Concomitant increase in vascular permeability caused by MIP-1, TNF-alpha and VEGF may lead to extravasation of chelated Gd or Gd-deposits. The inherent persistence of the Gd-deposits may subsequently result in an overactivation of pro-inflammatory pathways progressing towards overt skin effects.

Mesenchymal stem cells as vectors for lung disease

Stem cells divide asymmetrically, leading to self-renewal and the production of a daughter cell committed to differentiation. This property has engendered excitement as to the use of these cells for treatments. The majority of the work with stem cells has used the relatively accessible and well-characterized adult bone marrow stem cell compartment. Initially the focus of this research was on the potential for these stem cells to repair damaged organs by differentiating into epithelial cells to replace the injured areas. More recently it has become clear that engraftment of these stem cells as epithelial tissue is a rare event with perhaps limited clinical significance. Despite this, stem cells appear to have the ability to home to and be specifically recruited to areas of inflammation and injured tissues often characterized by excessive extracellular matrix deposition. As a consequence they are intimately involved in regions of physiological and pathological repair. Coupled with this, autologous hematopoietic stem cells, or the relatively immunoprivileged mesenchymal stem cells, can be expanded and engineered ex vivo and reintroduced without immunomodulation. The prospect of using such cells clinically as a cellular therapy holds much promise for many conditions and organ pathologies. Here we address the evidence for the incorporation of bone marrow stem cells into areas of stroma formation as a prelude to possible future treatment options for common lung diseases.

Plasticity after allogeneic hematopoietic stem cell transplantation

The postulated almost unlimited potential of transplanted hematopoietic stem cells (HSCs) to transdifferentiate into cell types that do not belong to the hematopoietic system denotes a complete paradigm shift of the hierarchical hemopoietic tree. In several studies during the last few years, donor cells have been identified in almost all recipient tissues after allogeneic HSC transplantation (HSCT), supporting the theory that any failing organ could be accessible to regenerative cell therapy. However, the putative potential ability of the stem cells to cross beyond lineage barriers has been questioned by other studies which suggest that hematopoietic cells might fuse with non-hematopoietic cells and mimic the appearance of transdifferentiation. Proof that HSCs have preserved the capacity to transdifferentiate into other cell types remains to be demonstrated. In this review, we focus mainly on clinical studies addressing plasticity in humans who underwent allogeneic HSCT. We summarize the published data on non-hematopoietic chimerism, donor cell contribution to tissue repair, the controversies related to the methods used to detect donor-derived non-hematopoietic cells and the functional impact of this phenomenon in diverse specific target tissues and organs.

Embryonic stem cell biology

ES cell research represents an exploding field of exploration. Initially predicted to provide rapid cures for numerous human diseases, the clinical usefulness of ES cell-derived cells remains untested in humans. However, ES cells have rapidly expanded our knowledge of human development and the molecular details of differentiation. Our ability to generate relatively pure populations of specifically differentiated cells for transplantation has markedly improved. It is hoped that soon researchers will overcome the biologic impediments to successful treatment of human disease with ES cell-derived cells.