Airway fistula closure after stem-cell infusion

Mesenchymal Stromal Cell Therapy for Thoracic Surgeons: An Update

Stem cells are undifferentiated cells presenting extensive self-renewal features and the ability to differentiate "in vitro" and "in vivo" into a range of lineage cells, like chondrogenic, osteogenic and adipogenic lineages when cultured in specific inducing media. Two major domains of clinical applications of stem cells in thoracic surgery have been investigated: regenerative medicine, which is a section of translational research in tissue engineering focusing on the replacement, renewal or regeneration of cells, tissues and organs to re-establish damaged physiologic functions; drug loading and delivery, representing a new branch proposing stem cells as carriers to provide selected districts with anti-cancer agents for targeted treatments.

Chinese expert consensus on interventional diagnosis and management of acquired digestive-respiratory tract fistulas (second edition)

Acquired digestive-respiratory tract fistulas occur with abnormal communication between the respiratory tract and digestive tract caused by a variety of benign or malignant diseases, leading to the alimentary canal contents in the respiratory tract. Although various departments have been actively exploring advanced fistula closure techniques, including surgical methods and multimodal therapy, some of which have gotten good clinical effects, there are few large-scale evidence-based medical data to guide clinical diagnosis and treatment. The guidelines update the etiology, classification, pathogenesis, diagnosis, and management of acquired digestive-respiratory tract fistulas. It has been proved that the implantation of the respiratory and digestive stent is the most important and best treatment for acquired digestive-respiratory tract fistulas. The guidelines conduct an in-depth review of the current evidence and introduce in detail the selection of stents, implantation methods, postoperative management and efficacy evaluation.

Development of Bio-artificial Esophageal Tissue Engineering Utilization for Circumferential Lesion Transplantation: A Narrative Review

The esophagus is the gastrointestinal tract's primary organ that transfers bolus into the stomach with peristaltic motion. Therefore, its lesions cause a significant disturbance in the nutrition and digestive system. Esophageal disease treatment sometimes requires surgical procedures that involve removal and circumferential full-thickness replacement. Unlike other organs, the esophagus has a limited regeneration ability and cannot be transplanted from donors. There are various methods of restoring the esophageal continuity; however, they are associated with certain flaws that lead to a non-functional recovery. As an exponentially growing science, tissue engineering has become a leading technique for the development of tissue replacement to repair damaged esophageal segments. Scaffold plays a significant role in the process of tissue engineering, as it acts as a template for the regeneration of growing tissue. A variety of scaffolds have been studied to replace the esophagus. Due to the many tissue quality challenges, the results are still inadequate and need to be improved. The success of esophageal tissue regeneration will finally depend on the scaffold's capability to mimic natural tissue properties and provide a qualified environment for regeneration. Thereby, scaffold fabrication techniques are fundamental. This article reviews the recent developments in esophageal tissue engineering for the treatment of circumferential lesions based on scaffold biomaterial engineering approaches.

The therapeutic effect of stem cells from human exfoliated deciduous teeth on a rat model of tracheal fistula

Background

Tracheal fistulas (TF) can be dangerous and even fatal in patients. The current treatment is really challenging. Previous studies reported that mesenchymal stem cells (MSCs) could be used to treat respiratory tract fistulas. Stem cells from human exfoliated deciduous teeth (SHED) are considered to be MSC-like cells that may also have the potential to treat the tracheal fistulas. In this study, we investigated the therapeutic effects of SHED in rat tracheal fistula models.

Methods

A total of 80 SD rats were randomly divided into five groups: a sham-operated group, a local PBS group (L-PBS), an intravenous PBS group (I-PBS), a local SHED treatment group (L-SHED), and an intravenous SHED treatment group (I-SHED). The L-SHED and I-SHED groups were given a topical application around the fistula or an intravenous injection of 1*10⁷ SHED via the tail vein, respectively, while the L-PBS and I-PBS groups were given an equivalent volume of PBS through local or intravenous administration. A stereomicroscope was used to observe fistula healing on the 2nd, 3rd, and 5th days following transplantation. On the 7th day, the survival of SHED was observed by immunofluorescence. The pathology of the lungs and fistulas was observed by hematoxylin and eosin (H&E) and Masson staining. The expression levels of the Toll-like receptor 4 (TLR4), interleukin (IL)-1β, IL-33, and IL-4 were measured using immunohistochemistry. The expression levels of TLR4, high mobility group box 1 (HMGB1), and myeloid differentiation factor 88 (MYD88) were studied using western blotting. On day 14, airway responsiveness of rats was detected and analyzed.

Results

Fistula healing in the L-SHED and I-SHED groups was faster than that in their respective PBS groups after transplantation. The fistula diameters in the L-SHED and I-SHED groups were significantly smaller than those in the L-PBS and I-PBS groups on the 3rd day. Moreover, the phenomenon of fibroblast proliferation and new blood vessel growth around the fistula seemed more pronounced in the L-SHED and I-SHED groups. Although no discernible difference was found in airway responsiveness after SHED treatment, the degree of inflammation in the lungs was reduced by intravenous SHED treatment. However, there was no significant reduction in lung inflammation by local SHED treatment. The expression levels of IL-1β and IL-33 were decreased in the I-SHED group, while IL-4 was elevated compared with the I-PBS group. Interestingly, intravenous SHED treatment inhibited the activation of HMGB1/TLR4/MYD88 in the lung tissues of TF rats.

Conclusions

SHED transplantation accelerated the rate of fistula healing in rats. Intravenous SHED treatment reduced lung inflammation. Thus, SHED may have potential in the treatment of tracheal fistula, providing hope for future therapeutic development for TF.

Mechanism of Action of Mesenchymal Stem Cells (MSCs): impact of delivery method

INTRODUCTION

Mesenchymal stromal cells (MSCs; AKA mesenchymal stem cells) stimulate healing and reduce inflammation. Promising therapeutic responses are seen in many late-phase clinical trials, but others have not satisfied their primary endpoints, making translation of MSCs into clinical practice difficult. These inconsistencies may be related to the route of MSC delivery, lack of product optimization, or varying background therapies received in clinical trials over time.

AREAS COVERED

Here we discuss the different routes of MSC delivery, highlighting the proposed mechanism(s) of therapeutic action as well as potential safety concerns. PubMed search criteria used: MSC plus: local administration; routes of administration; delivery methods; mechanism of action; therapy in different diseases.

EXPERT OPINION

Direct injection of MSCs using a controlled local delivery approach appears to have benefits in certain disease states, but further studies are required to make definitive conclusions regarding the superiority of one delivery method over another.

Ethanolamine Oleate for Bronchopleural Fistula: Case Series

BACKGROUND

Bronchopleural fistula (BPF) is a severe complication of pulmonary resection associated with high morbidity and mortality. Treatment options include both surgical and endoscopic procedures. The size of the fistula and the functional status of the patient are decisive factors in the choice of treatment. The aim of this study is to describe the experience of using ethanolamine oleate (EO) in endoscopic treatment for BPFs.

METHODS

A prospective observational, descriptive study, involving patients with subcentimeter BPF and treated with EO. The diagnosis of the fistula was confirmed by flexible bronchoscopy. Patients under conscious sedation received a perifistular injection of EO with a Wang 22-G needle. The procedure was repeated every to 2 weeks until definitive closure.

RESULTS

Eight patients were included: in 7 (87.5%), the fistula was a complication of lung cancer surgery. The number of sessions needed before the resolution of the BPF was from 1 to 4. Only 1 patient received 4 sessions. Complete closure was obtained in 6 patients (75%). None of the fistulas reopened, and there were no serious complications.

CONCLUSION

Sclerosis with EO through endoscopic injection enables the closure of small (<1 cm) BPFs after a limited number of sessions and with scarce morbidity. These results suggest that EO could be a valid treatment option for selected patients.

Biomimetic Design for Bio-Matrix Interfaces and Regenerative Organs

The urgent demand for transplanted organs has motivated the development of regenerative medicine to biomimetically reconstruct the structure and function of natural tissues or organs. The prerequisites for constructing multicellular organs include specific cell sources, suitable scaffolding material, and interconnective biofunctional interfaces. As some of the most complex systems in nature, human organs, tissues, and cellular units have unique "bio-matrix" physicochemical interfaces. Human tissues support a large number of cells with distinct biofunctional interfaces for compartmentalization related to metabolism, material exchange, and physical barriers. These naturally shaped biofunctional interfaces support critical metabolic functions that drive adaptive human behavior. In contrast, mutations and disorders during organogenesis can disrupt these interfaces as a consequence of disease and trauma. To replicate the appropriate structure and physiological function of tissues and organs, the biomaterials used in these approaches should have properties that mimic those of natural biofunctional interfaces. In this review, the focus is on the biomimetic design of functional interfaces and hierarchical structures for four regenerative organs, liver, kidney, lung, heart, and the immune system. Research on these organs provides understanding of cell-matrix interactions for hierarchically bioinspired material engineering, and guidance for the design of bioartificial organs. Finally, we provide perspectives on future challenges in biofunctional interface designs and discuss the obstacles that remain toward the generation of functional bioartificial organs.

Regenerative medicine approaches for the management of respiratory tract fistulas

Respiratory tract fistulas (or fistulae) are abnormal communications between the respiratory system and the digestive tract or the adjacent organs. The origin can be congenital or, more frequently, iatrogenic and the clinical presentation is heterogeneous. Respiratory tract fistulas can lead to severely reduced health-related quality of life and short survival. Therapy mainly relies on endoscopic surgical interventions but patients often require prolonged hospitalization and may develop complications. Therefore, more conservative regenerative medicine approaches, mainly based on lipotransfer, have also been investigated. Adipose tissue can be delivered either as unprocessed tissue, or after enzymatic treatment to derive the cellular stromal vascular fraction. In the current narrative review, we provide an overview of the main tissue/cell-based clinical studies for the management of various types of respiratory tract fistulas or injuries. Clinical experience is limited, as most of the studies were performed on a small number of patients. Albeit a conclusive proof of efficacy cannot be drawn, the reviewed studies suggest that grafting of adipose tissue-derived material may represent a minimally invasive and conservative treatment option, alternative to more aggressive surgical procedures. Knowledge on safety and tolerability acquired in prior studies can lead to the design of future, larger trials that may exploit innovative procedures for tissue processing to further improve the clinical outcome.

Differences in Mitochondrial Membrane Potential Identify Distinct Populations of Human Cardiac Mesenchymal Progenitor Cells

Adult human cardiac mesenchymal progenitor cells (hCmPC) are multipotent resident populations involved in cardiac homeostasis and heart repair. Even if the mechanisms have not yet been fully elucidated, the stem cell differentiation is guided by the mitochondrial metabolism; however, mitochondrial approaches to identify hCmPC with enhanced stemness and/or differentiation capability for cellular therapy are not established. Here we demonstrated that hCmPCs sorted for low and high mitochondrial membrane potential (using a lipophilic cationic dye tetramethylrhodamine methyl ester, TMRM), presented differences in energy metabolism from preferential glycolysis to oxidative rates. TMRM-high cells are highly efficient in terms of oxygen consumption rate, basal and maximal respiration, and spare respiratory capacity compared to TMRM-low cells. TMRM-high cells showed characteristics of pre-committed cells and were associated with higher in vitro differentiation capacity through endothelial, cardiac-like, and, to a lesser extent, adipogenic and chondro/osteogenic cell lineage, when compared with TMRM-low cells. Conversely, TMRM-low showed higher self-renewal potential. To conclude, we identified two hCmPC populations with different metabolic profile, stemness maturity, and differentiation potential. Our findings suggest that metabolic sorting can isolate cells with higher regenerative capacity and/or long-term survival. This metabolism-based strategy to select cells may be broadly applicable to therapies.

7-T MRI tracking of mesenchymal stromal cells after lung injection in a rat model

Background

Mesenchymal stromal cells (MSCs) are able to migrate and engraft at sites of inflammation, injuries, and tumours, but little is known about their fate after local injection. The purpose of this study is to perform MSC tracking, combining in vivo 7-T magnetic resonance imaging (MRI) and histological assessment, following lung injection in a rat model.

Methods

Five lungs were injected with ferumoxide-labelled MSCs and five with perfluorocarbon-labelled MSCs and underwent 7-T MRI. MRI acquisitions were recorded immediately (T₀), at 24 h (T₂₄) and/or 48 h (T₄₈) after injection. For each rat, labelled cells were assessed in the main organs by MRI. Target organs were harvested under sterile conditions from rats sacrificed 0, 24, or 48 h after injection and fixed for histological analysis via confocal and structured illumination microscopy.

Results

Ferumoxide-labelled MSCs were not detectable in the lungs, whereas they were not visible in the distant sites. Perfluorocarbon-labelled MSCs were seen in 5/5 injected lungs at T₀, in 1/2 at T₂₄, and in 1/3 at T₄₈. The fluorine signal in the liver was seen in 3/5 at T₀, in 1/2 at T24, and in 2/3 at T₄₈. Post-mortem histology confirmed the presence of MSCs in the injected lung.

Conclusions

Ferumoxide-labelled cells were not seen at distant sites; a linear decay of injected perfluorocarbon-labelled MSCs was observed at T₀, T₂₄, and T₄₈ in the lung. In more than half of the experiments, perfluorocarbon-labelled MSCs scattering to the liver was observed, with a similar decay over time as observed in the lung.

Endoscopic Lipofilling for the Treatment of Bronchopleural Fistulas After Anatomic Lung Resection

A bronchopleural fistula is a potentially fatal complication of anatomic lung resection surgery. Bronchoscopy has been described in the treatment of small-caliber fistulas. An endoscopic procedure based on instillation of mesenchymal stem cells for the treatment of bronchopleural fistula has recently been successful. Fat tissue is rich in mesenchymal stem cells, and we describe a technique based on the instillation of autologous fat (lipofilling) for the treatment of bronchopleural fistulas. The procedure was applied to 8 subjects affected by bronchopleural fistulas that were greater than 8 mm in diameter, and saw resolution in all cases.

Recent developments and advances in secondary prevention of lung cancer

Lung cancer prevention may include primary prevention strategies, such as corrections of working conditions and life style - primarily smoking cessation - as well as secondary prevention strategies, aiming at early detection that allows better survival rates and limited resections. This review summarizes recent developments and advances in secondary prevention, focusing on recent technological tools for an effective early diagnosis.

Mesenchymal Stromal Cell Therapeutic Delivery: Translational Challenges to Clinical Application

For several decades, multipotent mesenchymal stromal cells (MSCs) have been extensively studied for their therapeutic potential across a wide range of diseases. In the preclinical setting, MSCs demonstrate consistent ability to promote tissue healing, down-regulate excessive inflammation and improve outcomes in animal models. Several proposed mechanisms of action have been posited and demonstrated across an array of in vitro models. However, translation into clinical practice has proven considerably more difficult. A number of prominent well-funded late-phase clinical trials have failed, thus calling out for new efforts to optimize product delivery in the clinical setting. In this review, we discuss novel topics critical to the successful translation of MSCs from pre-clinical to clinical applications. In particular, we focus on the major routes of cell delivery, aspects related to hemocompatibility, and potential safety concerns associated with MSC therapy in the different settings.

Stem-Cell Therapy for Esophageal Anastomotic Leakage by Autografting Stromal Cells in Fibrin Scaffold

Esophageal anastomotic leakage (EAL) is a devastating complication for esophagectomy but the available therapies are unsatisfactory. Due to the healing effects of mesenchymal stromal cells (MSCs) and supporting capability of fibrin scaffold (FS), we evaluated the efficacy of a stem-cell therapy for EAL by engrafting adult and autologous MSCs (AAMSCs) in FS and investigated the potential mechanism. Twenty-one rabbits were assigned to AAMSC/FS group (n = 12) and control group (n = 9). After harvested, AAMSCs were identified and then labeled with lenti.GFP. To construct EAL model, a polyethylene tube was indwelled through the anastomosis for 1 week. A total of 2 × 106 AAMSCs in 0.2 ml FS were engrafted onto the EAL for the AAMSC/FS group, whereas FS was injected for control. Magnetic Resonance Imaging (MRI) examination was performed after 5 weeks. Esophageal tissues were harvested for macroscopic, histological analyses, Western blot, and immunohistochemistry at 8 weeks. The animal model of EAL was established successfully. MRI scanning revealed a decreased inflammation reaction in AAMSC/FS group. Accordingly, AAMSC/FS group presented a higher closure rate (83.3% vs. 11.1%, p = .02) and lower infection rate (33.3% vs. 88.9%, p = .02). Histological analyses showed the autografted MSCs resided in the injection site. Furthermore, milder inflammation responses and less collagen deposition were observed in AAMSC/FS group. Western blot and immunohistochemistry studies suggested that the therapeutic effect might be related to the secretions of IL-10 and MMP-9. Engrafting AAMSCs in FS could be a promising therapeutic strategy for the treatment of EAL by suppressing inflammation response and alleviating fibrosis progression. Stem Cells Translational Medicine 2019;8:548-556.

Bronchoscopic advances in the management of aerodigestive fistulas

Malignant aerodigestive fistula (ADF) is an uncommon condition complicating thoracic malignancies. It results in increased morbidity and mortality and warrants therapeutic intervention. The management approach depends on symptoms, configuration, location, and extent of the fistula. This article will discuss the therapeutic considerations in the management of ADF.

Management of Postpneumonectomy Bronchopleural Fistula: From Thoracoplasty to Transsternal Closure

Development of postpneumonectomy empyema with bronchopleural fistula is a life-threatening condition that requires prompt action. Although measures should be taken to prevent bronchopleural fistula at time of pneumonectomy, many patients experience this complication. Management focuses on drainage of the pleural space, control of the pleural infection including repair of the bronchopleural fistula, and obliteration of the residual pleural cavity. Multiple techniques and procedures have been developed over time to achieve these goals. Knowledge of the diverse therapeutic options is important to select the optimal treatment for these complex patients.

Closure of Bronchopleural Fistula with Mesenchymal Stem Cells: Case Report and Brief Literature Review

Closure of bronchopleural fistula remains a difficult challenge for clinicians. Although several therapeutic approaches have been proposed, the clinical results are commonly unsatisfactory. Previous reports have indicated that autologous mesenchymal stem cells (MSCs) are useful for aiding treatment of bronchopleural fistula. We report here the use of umbilical cord MSCs to effect the successful closure of a bronchopleural fistula (5 mm) in a 33-year-old woman 6 months after a lobectomy. A review of the relevant literature is included. The use of MSCs may be a promising therapeutic method for the closure of bronchopleural fistula. Randomized controlled trials with larger samples are required.

Chinese expert consensus on diagnosis and management of acquired respiratory-digestive tract fistulas

Acquired respiratory‐digestive tract fistulas occur with abnormal communication between the airways and digestive tract, causing the interflow of gas and liquid. Despite advances in surgical methods and the development of multimodal therapy in recent years, patients with acquired respiratory‐digestive tract fistulas continue to exhibit unfavorable clinical outcomes. Therefore, in order to guide clinical practice in China, the Respiratory and Cancer Intervention Alliance of the Beijing Health Promotion Association organized a group of experienced experts in the field to develop this consensus document. Based on a study of clinical application and expert experience in the diagnosis and management of acquired respiratory‐digestive tract fistulas at home and abroad, an Expert Consensus was developed. The panelists recruited comprised experts in pulmonology, oncology, thoracic surgery, interventional radiology, and gastroenterology. PubMed, Chinese Biology Abstract, Chinese Academic Journal, and Wanfang databases were used to identify relevant articles. The guidelines address etiology, classification, pathogenesis, diagnosis and management of acquired respiratory‐digestive tract fistulas. The statements on treatment focus on the indications for different procedures, technical aspects, and preprocedural, post‐procedural and complication management. The proposed guidelines for the diagnosis and management of acquired respiratory‐digestive tract fistulas are the first to be published by Chinese experts. These guidelines provide an in‐depth review of the current evidence and standard of diagnosis and management.

Artificial lung

Lung transplantation remains the definitive curative treatment for end-stage lung disease. However, future applications of tissue bioengineering could overcome the donor organ shortage and the need for immunosuppression. The final goal of lung tissue engineering is to recreate the whole spectrum of specialized lung tissues and thereby provide physiologic functions through bioengineered conducting airways, vasculature and gas exchange tissue. This review focuses on ongoing research in artificial lung development, open questions, achievements to date and how tissue engineering and stem cell technology may further contribute to the clinical application of bioartificial lungs. Although experimental transplantation of bioartificial lung developed by perfusing decellularized or synthetic scaffolds has been shown to provide gas exchange in vivo over a prolonged period, it should be clearly acknowledged that the development of a transplantable bioartificial lung is far from reality.

Bronchial carcinoid in anomalous right upper bronchus: a "patient-tailored" bronchoplasty resection technique

Bronchial carcinoids (BC) are indolent neuroendocrine tumors (NET) that are classified as malignant because they can locally infiltrate and metastasize. Resection is the primary treatment for most localized carcinoid tumors, with lung parenchymal-sparing surgery the favoured objective for patients with central airway tumors. Sleeve bronchoplasty techniques are complex surgical procedures defined as parenchyma-saving because they allow a radical resection with tumor-free margins while preserving the maximum amount of parenchyma. They are mainly indicated for tumors arising at the origin of a lobar bronchus, precluding simple lobectomy but not infiltrating so far as to require pneumonectomy. We describe a case of typical bronchial carcinoid of an anomalous right upper bronchus requiring a "patient-tailored" bronchoplasty technique. The surgical aspects and preoperative work-up are discussed.

Long-term regeneration and remodeling of the pig esophagus after circumferential resection using a retrievable synthetic scaffold carrying autologous cells

Treatment of esophageal disease can necessitate resection and reconstruction of the esophagus. Current reconstruction approaches are limited to utilization of an autologous conduit such as stomach, small bowel, or colon. A tissue engineered construct providing an alternative for esophageal replacement in circumferential, full thickness resection would have significant clinical applications. In the current study, we demonstrate that regeneration of esophageal tissue is feasible and reproducible in a large animal model using synthetic polyurethane electro-spun grafts seeded with autologous adipose-derived mesenchymal stem cells (aMSCs) and a disposable bioreactor. The scaffolds were not incorporated into the regrown esophageal tissue and were retrieved endoscopically. Animals underwent adipose tissue biopsy to harvest and expand autologous aMSCs for seeding on electro-spun polyurethane conduits in a bioreactor. Anesthetized pigs underwent full thickness circumferential resection of the mid-lower thoracic esophagus followed by implantation of the cell seeded scaffold. Results from these animals showed gradual structural regrowth of endogenous esophageal tissue, including squamous esophageal mucosa, submucosa, and smooth muscle layers with blood vessel formation. Scaffolds carrying autologous adipose-derived mesenchymal stem cells may provide an alternative to the use of a gastro-intestinal conduit for some patients following resection of the esophagus.

Stem Cells Application in Thoracic Surgery: Current Perspective and Future Directions

Two main fields of clinical applications of stem cells in thoracic surgery have been explored: (a) regenerative medicine, that is a branch of translational research in tissue engineering and molecular biology dealing with the replacement, engineering or regeneration of cells, tissues and organs to restore normal function; (b) drug loading and delivery, that is an emerging field proposing stem cells as vectors to deliver anti-cancer agents for targeted therapies.Bronchopleural fistula is a pathological connection between the bronchus and the pleural cavity that may develop after lung resection, thus causing pleural empyema due to colonization by resident airway bacteria; stem cells and regenerative medicine approach can effectively contribute to impaired bronchial healing, thus preventive a septic and ventilator catastrophe.In the field of thoracic oncology, MSC are probably one of the best choice for anticancer drug delivery, emerging as potential experimental approach to malignant mesothelioma treatment.The goal of this review is to focus on clinical applications of stem cell technologies in thoracic surgery, emphasizing regenerative medicine aspects as well as drug loading and delivery in thoracic oncology.

Mesenchymal Stromal Cells for Antineoplastic Drug Loading and Delivery

Mesenchymal stromal cells are a population of undifferentiated multipotent adult cells possessing extensive self-renewal properties and the potential to differentiate into a variety of mesenchymal lineage cells. They express broad anti-inflammatory and immunomodulatory activity on the immune system and after transplantation can interact with the surrounding microenvironment, promoting tissue healing and regeneration. For this reason, mesenchymal stromal cells have been widely used in regenerative medicine, both in preclinical and clinical settings. Another clinical application of mesenchymal stromal cells is the targeted delivery of chemotherapeutic agents to neoplastic cells, maximizing the cytotoxic activity against cancer cells and minimizing collateral damage to non-neoplastic tissues. Mesenchymal stem cells are home to the stroma of several primary and metastatic neoplasms and hence can be used as vectors for targeted delivery of antineoplastic drugs to the tumour microenvironment, thereby reducing systemic toxicity and maximizing antitumour effects. Paclitaxel and gemcitabine are the chemotherapeutic drugs best loaded by mesenchymal stromal cells and delivered to neoplastic cells, whereas other agents, like pemetrexed, are not internalized by mesenchymal stromal cells and therefore are not suitable for advanced antineoplastic therapy. This review focuses on the state of the art of advanced antineoplastic cell therapy and its future perspectives, emphasizing in vitro and in vivo preclinical results and future clinical applications.

Bronchopleural Fistula After Pneumonectomy: Risk Factors and Management, Focusing on Open-Window Thoracostomy

We evaluated principal risk factors and different therapeutic approaches for post-pneumonectomy bronchopleural fistula (BPF), focusing on open-window thoracostomy (OWT). We retrospectively reviewed all patients treated by pneumonectomy for lung cancer from 1999 to 2014; we evaluated preoperative, operative, and postoperative data; time between operation; and fistula formation, size, treatment, and predicting factors of BPF. Cumulative incidence curves for the development of BPF were drawn according to the Kaplan-Meier method. Differences between groups were assessed with the log rank test. Multivariable Cox proportional hazards regression analysis was used to assess the independent risk factors for BPF. P values <0.05 were considered significant. BPF occurred in 60 of 733 patients (8.2%). Bronchial suture with Stapler (EndoGia) (P = 0.02), right side (P = 0.003), and low preoperative albumin levels (< 3.5 g/dL) (P = 0.02) were independent predicting factors of fistula. Early BPF was treated by thoracotomic (12) or thoracoscopic (2) debridement of necrotic tissue and BPF surgical repair. Late BPF was treated by bronchoscopic application of fibrin glue (3) or endobronchial stent (1), chest tube and cavity irrigation by povidone-iodine (15). OWT was performed in 27 patients, followed by muscle flap interposition in 7 of these 27. The survival time of patients after the treatment of BPF was 29.0 months. The overall survival of patients treated by OWT was 50% at 2 years and 27 (8%) at 4 years. Correct management of BPF depends on several factors. In case of failure of different initial therapeutic approaches, we could consider OWT, followed by myoplasty.

Transplanted fibroblasts proliferate in host bronchial tissue and enhance bronchial anastomotic healing in a rodent model

INTRODUCTION

Healing of airway anastomoses after preoperative irradiation can be a significant clinical problem. The augmentation of bronchial anastomoses with a fibroblast-seeded human acellular dermis (hAD) was shown to be beneficial, although the underlying mechanism remained unclear. Therefore, in this study we investigated the fate of the fibroblasts transplanted to the scaffold covering the anastomosis.

MATERIAL AND METHODS

32 Fisher rats underwent surgical anastomosis of the left main bronchus. In a 2 × 2 factorial design, they were randomized to receive preoperative irradiation of 20 Gy and augmentation of the anastomosis with a fibroblast-seeded transplant. Fibroblasts from subcutaneous fat of Fischer-344 rat were transduced retrovirally with tdTomato for cell tracking. After 7 and 14 days, animals were sacrificed and cell concentration of transplanted and nontransplanted fibroblasts in the hAD as well as in the bronchial tissue was measured using RT-PCR.

RESULTS

Migration of transplanted fibroblasts from dermis to bronchus were demonstrated in both groups, irradiated and nonirradiated. In the irradiated groups, there was a cell count of 7 × 104 ± 1 × 104 tomato+-fibroblasts in the bronchial tissue at day 7, rising to 1 × 105 ± 1 × 104 on day 14 (p <0.0001). Tomato+-cell concentration in hAD increased from 6 × 103 ± 1 × 103 at day 7 to 6 × 104 ± 1 × 104 at day 14 (p <0.0001). In the nonirradiated groups, tomato+-cell concentration in bronchus was 4 × 103 ± 1 × 103 on day 7 and 4 × 103 ± 1 × 103 at day 14. In the hAD tomato+ cell concentration rising from 1 × 104 ± 1 × 103 at day 7 to 2 × 104 ± 3 × 103 cells at day 14 (p = 0.0028).

CONCLUSIONS

Transplanted fibroblasts in the irradiated groups proliferate and migrate into the irradiated host bronchial tissue, but not in the nonirradiated groups.

WITHDRAWN: Bronchopleural fistula after pneumonectomy: Risk factors and management, focusing on open window thoracostomy

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Current treatment of tracheoesophageal fistula

Tracheoesophageal fistulas (TEFs) often occur with esophageal or bronchial carcinoma. Currently, we rely on implantation of delicate devices, such as self-expanding and silicone stents, in the esophagus or trachea to cover the fistula and expand the stenosis in order to relieve patient pain. However, because each case is different, our approach may not be effective for every patient. Consequently, new devices and technology have emerged to address these situations, such as degradable stents, Amplatzer^® devices, endobronchial one-way umbrella-shaped valves, and transplantation of mesenchymal stem cells. Although some studies have shown such alternatives can be reasonable solutions in special cases, further development of other new and effectual techniques is of utmost importance.

Closure of a Recurrent Bronchopleural Fistula Using a Matrix Seeded With Patient-Derived Mesenchymal Stem Cells

This is the first-in-human application of an autologous mesenchymal stem cell (MSC)-seeded matrix graft to repair a multiply recurrent postpneumonectomy bronchopleural fistula (BPF). Adipose-derived MSCs were isolated from patient abdominal adipose tissue, expanded, and seeded onto bio-absorbable mesh, which was surgically implanted at the BPF site. After clinical follow-up of 1.5 years, the patient is clinically asymptomatic without evidence of recurrence or malignant degeneration of MSC populations in situ.

Management of recurrent bronchopleural fistula (BPF) after pneumonectomy remains a challenge. Although a variety of devices and techniques have been described, definitive management usually involves closure of the fistula tract through surgical intervention. Standard surgical approaches for BPF incur significant morbidity and mortality and are not reliably or uniformly successful. We describe the first-in-human application of an autologous mesenchymal stem cell (MSC)-seeded matrix graft to repair a multiply recurrent postpneumonectomy BPF. Adipose-derived MSCs were isolated from patient abdominal adipose tissue, expanded, and seeded onto bio-absorbable mesh, which was surgically implanted at the site of BPF. Clinical follow-up and postprocedural radiological and bronchoscopic imaging were performed to ensure BPF closure, and in vitro stemness characterization of patient-specific MSCs was performed. The patient remained clinically asymptomatic without evidence of recurrence on bronchoscopy at 3 months, computed tomographic imaging at 16 months, and clinical follow-up of 1.5 years. There is no evidence of malignant degeneration of MSC populations in situ, and the patient-derived MSCs were capable of differentiating into adipocytes, chondrocytes, and osteocytes using established protocols. Isolation and expansion of autologous MSCs derived from patients in a malnourished, deconditioned state is possible. Successful closure and safety data for this approach suggest the potential for an expanded study of the role of autologous MSCs in regenerative surgical applications for BPF.

Significance

Bronchopleural fistula is a severe complication of pulmonary resection. Current management is not reliably successful. This work describes the first-in-human application of an autologous mesenchymal stem cell (MSC)-seeded matrix graft to the repair of a large, multiply recurrent postpneumonectomy BPF. Clinical follow-up of 1.5 years without recurrence suggests initial safety and feasibility of this approach. Further assessment of MSC grafts in these difficult clinical scenarios requires expanded study.

Therapeutic options following pneumonectomy in non-small cell lung cancer

INTRODUCTION

Pneumonectomy can be considered the most appropriate treatment for lung cancer that cannot be removed by lesser resection on.

AREAS COVERED

Therapeutic options following pneumonectomy may be required at least in 3 different scenarios: 1) an early approach due to acute surgical complications 2) a late approach due to chronic surgical complications 3) an integrated radio-chemotherapeutic adjuvant approach for advanced stages. In this review we focused on these three settings with particular emphasis to surgical approach as well as to alternative options. Expert commentary: Pneumonectomy itself does not preclude postoperative additional treatments, if needed, to maximize oncological results and to manage potential short or long term complications. However, as pneumonectomy puts a significant physiological stress on the respiratory and circulatory systems, the benefits and risks of pneumonectomy should be compared with those of alternative, non-resectional treatment modalities.

A phase I study for intravenous autologous mesenchymal stromal cell administration to patients with severe emphysema

BACKGROUND

Mesenchymal stromal cells (MSCs) may reduce inflammation and promote tissue repair in pulmonary emphysema.

AIM

To study the safety and feasibility of bone marrow-derived autologous (BM-) MSC intravenous administration to patients with severe emphysema.

DESIGN

A phase I, prospective open-label study registered at ClinicalTrials.gov as NCT01306513 Eligible patients had lung volume reduction surgery (LVRS) on two separate occasions. During the first LVRS bone marrow was collected, from which MSCs were isolated and expanded ex vivo After 8 weeks, patients received two autologous MSC infusions 1 week apart, followed by the second LVRS procedure at 3 weeks after the second BM-MSC infusion.

METHODS

Up to 3 weeks after the last MSC infusion adverse events were recorded. Using immunohistochemistry and qPCR for analysis of cell and proliferation markers, emphysematous lung tissue obtained during the first surgery was compared with lung tissue obtained after the second surgical session to assess BM-MSC effects.

RESULTS

From 10 included patients three were excluded: two did not receive MSCs due to insufficient MSC culture expansion, and one had no second surgery. No adverse events related to MSC infusions occurred and lung tissue showed no fibrotic responses. After LVRS and MSC infusions alveolar septa showed a 3-fold increased expression of the endothelial marker CD31 (P  =  0.016).

CONCLUSIONS

Autologous MSC treatment in severe emphysema is feasible and safe. The increase in CD31 expression after LVRS and MSC treatment suggests responsiveness of microvascular endothelial cells in the most severely affected parts of the lung.

Historical perspectives of bronchoscopy. Connecting the dots

The era of bronchoscopy began with Gustav Killian in 1876 when he removed a pork bone from a farmer's airway, using an esophagoscope. Prompted by this accomplishment, Chevalier Jackson, an American otolaryngologist, laid the platform for the modern-day rigid bronchoscope in the early twentieth century. In 1967 Shigeto Ikeda revolutionized the field of bronchoscopy by his innovation of the fiberoptic bronchoscope. Today, bronchoscopy and interventional pulmonology have become an integral part of pulmonary medicine and an established subspecialty. Numerous innovators have furthered the horizons of this technology. In the early 1980s Ko-Pen Wang introduced transbronchial needle aspiration to sample mediastinal lesions while Jean-François Dumon developed methods for laser photoresection and for placing stents thorough the bronchoscope. More recently, application of endobronchial ultrasound and electromagnetic navigation tools has further galvanized the role of bronchoscopy. The success of lung transplantation also belongs in part to flexible bronchoscopy. Today, researchers are looking into treating emphysema as well as asthma, using bronchoscopic techniques. We believe 2015 is a good time to look back on the history of bronchoscopy and to recognize its major milestones. This article attempts to connect the historical dots in this field of research, with the hope that our effort helps future generations improve the welfare of patients with lung ailments.

Current Perspectives in Mesenchymal Stromal Cell Therapies for Airway Tissue Defects

Lung cancer is the leading cause of cancer death and respiratory diseases are the third cause of death in industrialized countries; for this reason the airways and cardiopulmonary system have been the focus of extensive investigation, in particular of the new emerging branch of regenerative medicine. Mesenchymal stromal cells (MSCs) are a population of undifferentiated multipotent adult cells that naturally reside within the human body, which can differentiate into osteogenic, chondrogenic, and adipogenic lineages when cultured in specific inducing media. MSCs have the ability to migrate and engraft at sites of inflammation and injury in response to cytokines, chemokines, and growth factors at a wound site and they can exert local reparative effects through transdifferentiation and differentiation into specific cell types or via the paracrine secretion of soluble factors with anti-inflammatory and wound-healing activities. Experimental and clinical evidence exists regarding MSCs efficacy in airway defects restoration; although clinical MSCs use, in the daily practice, is not yet completely reached for airway diseases, we can argue that MSCs do not represent any more merely an experimental approach to airway tissue defects restoration but they can be considered as a “salvage” therapeutic tool in very selected patients and diseases.

The Rationale for Treatment of Postresectional Bronchopleural Fistula: Analysis of 52 Patients

BACKGROUND

Bronchopleural fistulas are a major therapeutic challenge. We have reviewed our experience to establish the best choice of treatment.

METHODS

From January 2001 to December 2013, the records of 3,832 patients who underwent pulmonary anatomic resections were retrospectively reviewed.

RESULTS

The overall incidence of bronchopleural fistulas was 1.4% (52 of 3,832): 1.2% after lobectomy and 4.4% after pneumonectomy. Pneumonectomy vs lobectomy, right-sided vs left-sided resection, and hand-sewn closure of the stump vs stapling showed a statistically significant correlation with fistula formation. Primary bronchoscopic treatment was performed in 35 of 52 patients (67.3%) with a fistula of less than 1 cm and with a viable stump. The remaining 17 patients (32.7%) underwent primary operation. The fistula was cured with endoscopic treatment in 80% and with operative repair in 88.2%. Cure rates were 62.5% after pneumonectomy and 86.4% after lobectomy. The cure rate with endoscopic treatment was 92.3% in very small fistulas, 71.4% in small fistulas, and 80% in intermediate fistulas. The cure rate after surgical treatment was 100% in small fistulas, 75% in intermediate fistulas, and 100% in very large fistulas. Morbidity and mortality rates were 5.8% and 3.8%, respectively.

CONCLUSIONS

The bronchoscopic approach shows very promising results in all but the largest bronchopleural fistulas. Very small, small, and intermediate fistulas with a viable bronchial stump can be managed endoscopically, using mechanical abrasion, polidocanol sclerosing agent, and cyanoacrylate glue. Bronchoscopic treatment can be repeated, and if it fails, does not preclude subsequent successful surgical treatment.