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BACKGROUND Airway release (AR) maneuvers performed during airway resection to reduce anastomotic tension have not been thoroughly studied. METHODS This study retrospectively analyzed consecutive resections for postintubation stenosis (PITS) and primary tracheal neoplasms (PTNs) at Massachusetts General Hospital (Boston, MA). Anastomotic complications were defined as stenosis, separation, necrosis, granulation tissue, and air leak. Logistic regression modeling was used to identify factors associated with AR and adverse outcome. RESULTS From 1993 to 2019, 545 patients with PITS (375; 68.8%) and PTNs (170; 31.2%) underwent laryngotracheal, tracheal, or carinal (resections and reconstructions; 5.7% (31 of 545) were reoperations. AR was performed in 11% (60 of 545): in 3.8% of laryngotracheal resections (6 of 157; all laryngeal), in 9.8% of tracheal resections (34 of 347; laryngeal, 12, and hilar, 22), and in 49% of carinal resections (20 of 41; laryngeal, 1, and hilar, 19). Mean resected length was 3.5 cm (range, 1to- 6.3 cm) with AR and 3.0 cm (range, 0.8 to 6.5 cm) without AR (P < .01). Operative mortality was 0.7% (4 of 545); all 4 anastomoses were intact until death. Anastomotic complications were present in 5% of patients who underwent AR (3 of 60) and in 9.3% (45 of 485) of patients who did not. AR was associated with resection length of 4 cm or longer (odds ratio [OR], 6.15; 95% confidence interval [CI], 1.37 to 27.65), PTNs (OR, 7.81; 95% CI, 3.31 to 18.40), younger age (OR, 0.96; 95% CI, 0.94 to 0.98), and lung resection (OR, 6.09; 95% CI, 1.33 to 27.90). Anastomotic complications in patients with tracheal anastomoses were associated with preexisting tracheostomy (OR, 2.68; 95% CI, 1.50 to 4.80), but not release. CONCLUSIONS Tracheal reconstruction succeeds, even when anastomotic tension requires AR. Because intraoperative assessment may underestimate tension, lowering the threshold for AR seems prudent, particularly in patients with diabetes.

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 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 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.

Lung transplantation is currently the only curative treatment for patients with end-stage lung disease; however, donor organ shortage and the need for intense immunosuppression limit its broad clinical application. Bioartificial lungs created by combining native matrix scaffolds with patient-derived cells might overcome these problems. Decellularization involves stripping away cells while leaving behind the extracellular matrix scaffold. Cadaveric lungs are decellularized by detergent perfusion, and histologic examination confirms the absence of cellular components but the preservation of matrix proteins. The resulting lung scaffolds are recellularized in a bioreactor that provides biomimetic conditions, including vascular perfusion and liquid ventilation. Cell seeding, engraftment, and tissue maturation are achieved in whole-organ culture. Bioartificial lungs are transplantable, similarly to donor lungs, because the scaffolds preserve the vascular and airway architecture. In rat and porcine transplantation models, successful anastomoses of the vasculature and the airway were achieved, and gas exchange was evident after reperfusion. However, long-term function has not been achieved because of the immaturity of the vascular bed and distal lung epithelia. The goal of this strategy is to create patient-specific transplantable lungs using induced pluripotent stem cell (iPSC)-derived cells. The repopulation of decellularized scaffolds to create transplantable organs is one of possible future clinical applications of iPSCs.

Objectives The study objectives were to evaluate the immediate, short-, and medium-term efficacy and safety of pulmonary artery branch sealing using an ultrasonic vessel-sealing device in minimally invasive anatomic lung resection. Methods This study consists of a prospective, phase 2, multicenter, international clinical trial (clinicaltrials.gov: NCT02719717) that enrolled patients planned for video-assisted thoracoscopic surgery/robotic anatomic lung resection in 7 centers (United States, Canada, United Kingdom). Pulmonary artery branches of 7 mm or less were sealed and divided with an ultrasonic energy vessel-sealing device. The remainder of the lobectomy was performed according to surgeon preference. Intraoperative, in-hospital, and 30-day postoperative bleeding and complications were prospectively recorded. Results A total of 150 patients with a minimum of 1 pulmonary artery branch sealed with an ultrasonic vessel-sealing device were prospectively enrolled in the trial. Resections included 139 lobectomies and 11 segmentectomies. A total of 424 pulmonary artery branches were divided: 239 with the ultrasonic vessel-sealing device, 181 with endostaplers, and 4 with endoscopic clips. The mean and median pulmonary artery diameters were 4.7 mm/5.0 mm, 10.3 mm/10.0 mm, and 6.5 mm/6.5 mm for each method, respectively. Three of the pulmonary artery branches divided with the ultrasonic vessel-sealing device (1.3%) and 4 pulmonary artery branches divided with endostaplers (2.2%) bled intraoperatively. Among the patients with seal failures, 1 patient required conversion to thoracotomy. There was no postoperative bleeding from divided pulmonary artery branches with either sealing method. There was no mortality at 30 days. Conclusions Pulmonary artery branch sealing with ultrasonic energy during video-assisted thoracoscopic surgery lobectomy is safe for vessels 7 mm or less. The use of an ultrasonic device is a reasonable sealing method for pulmonary artery branches 7 mm or less.

Summary Background Esophageal perforation is a morbid condition and remains a therapeutic challenge. We report the outcomes of a large institutional experience with esophageal perforation and identify risk factors for morbidity and mortality. Methods A retrospective analysis was conducted on 142 patients who presented with a thoracic or gastroesophageal junction esophageal perforation from 1995 to 2020. Baseline characteristics, operative or interventional strategies, and outcomes were analyzed by etiology of the perforation and management approach. Multivariable cox and logistic regression models were constructed to identify predictors of mortality and morbidity. Results Overall, 109 (77%) patients underwent operative intervention, including 80 primary reinforced repairs and 21 esophagectomies and 33 (23%) underwent esophageal stenting. Stenting was more common in iatrogenic (27%) and malignant (64%) perforations. Patients who presented with a postemetic or iatrogenic perforation had similar 90-day mortality (16% and 16%) and composite morbidity (51% and 45%), whereas patients who presented with a malignant perforation had a 45% 90-day mortality and 45% composite morbidity. Risk factors for mortality included age >65 years (hazard ratio [HR] 1.89 [1.02–3.26], P = 0.044) and a malignant perforation (HR 4.80 [1.31–17.48], P = 0.017). Risk factors for composite morbidity included pleural contamination (odds ratio [OR] 2.06 [1.39–4.43], P = 0.046) and sepsis (OR 3.26 [1.44–7.36], P = 0.005). Of the 33 patients who underwent stent placement, 67% were successfully managed with stenting alone and 30% required stent repositioning. Conclusions Risk factors for morbidity and mortality after esophageal perforation include advanced age, pleural contamination, septic physiology, and malignant perforation. Primary reinforced repair remains a reasonable strategy for patients with an esophageal perforation from a benign etiology.

Lung transplantation is the only treatment for end-stage lung disease; however, donor organ shortage and intense immunosuppression limit its broad clinical impact. Bioengineering of lungs with patient-derived cells could overcome these problems. We created bioartificial lungs by seeding human-derived cells onto porcine lung matrices and performed orthotopic transplantation to assess feasibility and in vivo function. Porcine decellularized lung scaffolds were seeded with human airway epithelial cells and human umbilical vein endothelial cells. Following in vitro culture, the bioartificial lungs were orthotopically transplanted into porcine recipients with planned 1-day survival (n = 3). Lungs were assessed with histology and in vivo function. Orthotopic transplantation of cadaveric lungs was performed as control. Engraftment of endothelial and epithelial cells in the grafts were histologically demonstrated. Technically successful orthotopic anastomoses of the vasculatures and airway were achieved in all animals. Perfusion and ventilation of the lung grafts were confirmed intraoperatively. The gas exchange function was evident immediately after transplantation; PO2 gradient between pulmonary artery and vein were 178 ± 153 mm Hg in the bioartificial lung group and 183 ± 117 mm Hg in the control group. At time of evaluation 24 hours after reperfusion, the pulmonary arteries were found to be occluded with thrombus in all bioartificial lungs. Engineering and orthotopic transplantation of bioartificial lungs with human cells were technically feasible in a porcine model. Early gas exchange function was evident. Further progress in optimizing recellularization and maturation of the grafts will be necessary for sustained perfusability and function.

Approximately 10% to 15% of patients with solitary fibrous tumors of the pleura (SFTP) have recurrence after resection. Many are not candidates for reresection and lack effective treatments. We explored the expression of programmed death ligand 1 (PD-L1) as a biomarker for candidacy for treatment with immune checkpoint inhibitors.We reviewed the medical records of 52 patients with primary SFTP and 5 with recurrent SFTP. We performed immunohistochemistry on tumor tissue to determine the expression of PD-L1 and infiltration by cluster of differentiation 8 (CD8)-positive immune cells.Any PD-L1 expression was observed in 11 primary SFTP (21.2%). Overall, PD-L1 expression level was less than 1% in 10 patients (19.2%) and greater than 1% in 1 (1.9%). Tumor infiltration by CD8-positive immune cells was absent or rare in 13 patients (25%), less than 5% in 31 (59.6%), and 5% to 25% in 8 (15.4%). There were no associations between PD-L1 expression or immune cell infiltrates and known risk factors for recurrence or a prognostic risk score classification. Time to recurrence was strongly associated with the risk score classification (P.001), but it was not associated with PD-L1 expression (P = .296) or immune cell infiltrates (P = .619). In recurrent SFTP, PD-L1 was expressed in 4 of 10 tumors (40%; all1% expression). There was no correlation in PD-L1 expression between primary and recurrent SFTP samples.A small subset of SFTP express PD-L1 at low levels (1%) but exhibit colocalization of CD8-positive immune cells suggesting an inducible expression mechanism. The role of PD-L1 merits exploration in the clinical setting in patients with advanced SFTP when alternative treatments or clinical trials are considered.

The human trachea is a vital structure with complex architecture and well-defined mechanical properties. Trauma, neoplasm, congenital defects and iatrogenic injury can lead to loss of patency and necessitate surgical intervention to reestablish its function as a viable and disease resistant airway. Due to the trachea’s structural redundancy, and longitudinal elasticity, circumferential tracheal resection and primary anastomosis is safe in the majority of patients. For those who require removal of more than half of the trachea, options are limited. This unmet need, and the apparent simplicity of the trachea as a hollow tube, have inspired surgeons and scientists to engineer tracheal substitutes over nearly a century. None of these implants have achieved long term patency. As a result, patients have suffered from complications of premature clinical translation. While experimental research in this area has to continue, engineered tissues are not a viable form of treatment at this point in time.

In reconstructive surgery, transfer of patients' tissue (autologous flaps) is routinely used to repair large soft tissue defects caused by surgery, trauma, chronic diseases, or malformations; unfortunately, this strategy is not always possible and often creates a secondary defect in the donor site of the tissue. Tissue-engineered synthetic flaps are currently unable to repair clinically-relevant, large-volume defects; allogenic flaps from cadaveric donors could provide a ready-to-use biological alternative if treated with methods to avoid the immune-rejection of the donor's cells. Here, we describe the successful decellularization of a large (> 800 cc) human-derived adipose flap through a perfusion apparatus; we demonstrate the complete removal of the immunogenic cellular components of the flap with the retention of its structural components and vascular network. Our aim is to obtain a universally compatible, off-the-shelf acellular allogenic flap that could be recellularized with cells from recipient patients to provide a tissue-engineered allogenic/autologous alternative for reconstruction of large-volume soft-tissue defects.

Video-assisted thoracic surgery (VATS) and robotically assisted surgery are used increasingly for minimally invasive diagnostic and therapeutic resection of pulmonary nodules. Unsuccessful localization of small, impalpable, or deep pulmonary nodules can necessitate conversion from VATS to open thoracotomy. Preoperative localization techniques performed by radiologists have improved the success rates of VATS resection for small and subsolid nodules. Any center at which VATS diagnostic resection of indeterminate pulmonary nodules is performed should be supported by radiologists who offer preoperative nodule localization. Many techniques have been described, including image-guided injection of radioisotopes and radiopaque liquids and placement of metallic wires, coils, and fiducial markers. These markers enable the surgeon to visualize the position of an impalpable nodule intraoperatively. This article provides details on how to perform each percutaneous localization technique, and a group of national experts with established nodule localization programs describe their preferred approaches. Special reference is made to equipment required, optimization of marker placement, prevention of technique-specific complications, and postprocedural treatment. This comprehensive unbiased review provides valuable information for those who are considering implementation or optimization of a nodule localization program according to workflow patterns, surgeon preference, and institutional resources in a particular center. ©RSNA, 2019.

Background To evaluate the management, complications of treatment, and outcomes of postintubation tracheal stenosis. Methods A retrospective review was performed of records from a prospective database of all patients undergoing tracheal or laryngotracheal resection from 1993 to 2017 for postintubation tracheal stenosis. Redo operations after failure of initial resection and reconstruction for postintubation tracheal stenosis were included. Results There were 392 patients whose ages ranged from 3 months to more than 84 years. A tracheostomy was performed in 275 as part of their care before surgery (present at time of resection in 123), dilations in 201, laser treatment in 82, T tubes in 66, and stents in 44 patients. Median length of resection was 3 cm. Laryngeal release was required in 15 of 392 (3.8%). Operative mortality was 0.8% (3 of 392); T tubes, tracheostomy present at resection, requirement for postoperative tracheostomy, and laryngeal involvement adversely impacted outcomes. Patients having tracheal resection and reconstruction had good or satisfactory outcomes in 96% (289 of 301) compared with 85% (77 of 91) having laryngotracheal resection. Complications within 30 days and at more than 30 days occurred in 116 patients and 14 patients, respectively. There were 96 anastomotic complications—68% minor (65 of 96), and 32% major (31 of 96). Necrosis of cartilage occurred in 12 patients and dehiscence in 14 patients. Conclusions Despite advances in care postintubation tracheal stenosis remains a challenging problem. Laryngotracheal resection and tracheostomy lead to worse outcomes. Excellent surgical results can be obtained for postintubation tracheal stenosis. Good results require careful evaluation, management of comorbid conditions, meticulous technique, minimizing tension, and preservation of blood supply.

Whole lung extracellular matrix scaffolds can be created by perfusion of cadaveric organs with decellularizing detergents, providing a platform for organ regeneration. Lung epithelial engineering must address both the proximal airway cells that function to metabolize toxins and aid mucociliary clearance and the distal pneumocytes that facilitate gas exchange. Engineered pulmonary vasculature must support in vivo blood perfusion with low resistance and intact barrier function and be antithrombotic. Repopulating the native lung matrix with sufficient cell numbers in appropriate anatomic locations is required to enable organ function.

Rationale: More than 25 million individuals have heart failure worldwide, with ≈4000 patients currently awaiting heart transplantation in the United States. Donor organ shortage and allograft rejection remain major limitations with only ≈2500 hearts transplanted each year. As a theoretical alternative to allotransplantation, patient-derived bioartificial myocardium could provide functional support and ultimately impact the treatment of heart failure. Objective: The objective of this study is to translate previous work to human scale and clinically relevant cells for the bioengineering of functional myocardial tissue based on the combination of human cardiac matrix and human induced pluripotent stem cell–derived cardiomyocytes. Methods and Results: To provide a clinically relevant tissue scaffold, we translated perfusion-decellularization to human scale and obtained biocompatible human acellular cardiac scaffolds with preserved extracellular matrix composition, architecture, and perfusable coronary vasculature. We then repopulated this native human cardiac matrix with cardiomyocytes derived from nontransgenic human induced pluripotent stem cells and generated tissues of increasing 3-dimensional complexity. We maintained such cardiac tissue constructs in culture for 120 days to demonstrate definitive sarcomeric structure, cell and matrix deformation, contractile force, and electrical conduction. To show that functional myocardial tissue of human scale can be built on this platform, we then partially recellularized human whole-heart scaffolds with human induced pluripotent stem cell–derived cardiomyocytes. Under biomimetic culture, the seeded constructs developed force-generating human myocardial tissue and showed electrical conductivity, left ventricular pressure development, and metabolic function. Conclusions: Native cardiac extracellular matrix scaffolds maintain matrix components and structure to support the seeding and engraftment of human induced pluripotent stem cell–derived cardiomyocytes and enable the bioengineering of functional human myocardial-like tissue of multiple complexities.

Pulmonary resections with concomitant circumferential airway resection and resection and reconstruction of carina and main stem bronchi remain challenging operations in thoracic surgery. Anastomotic complications range from mucosal sloughing and formation of granulation tissue, anastomotic ischemia promoting scar formation and stricture, to anastomotic breakdown leading to bronchopleural or bronchovascular fistulae or complete dehiscence. Careful attention to patient selection and technical detail results in acceptable morbidity and mortality as well as good long-term survival. In this article, we focus on the technical details of the procedures, how to avoid complications and most importantly how to manage complications when they occur.

Objective Pulmonary nodules found incidentally or by lung cancer screening differ in prevalence, risk profile, and diagnostic intervention. The results of surgical intervention for incidental versus screening lung nodules during multidisciplinary Pulmonary Nodule and Lung Cancer Screening Clinic (PNLCSC) follow-up have not been reported. Methods All patients evaluated at a PNLCSC from 2012 to 2018 following referral by primary care physicians, specialist physicians, or self-referral after computed tomography (CT) identified nodules on routine diagnostic CT (incidental group) or lung cancer screening CT (screening group) were included. Follow-up interval, invasive intervention, histology, postoperative events, survival, and recurrence were compared. Results Of 747 patients evaluated in the PNLCSC, 129 (17.2%) underwent surgical intervention. The surgical cohort consisted of 104 (80.6%) incidental and 25 (19.3%) screening patients followed over a mean of 122 and 70 days, respectively. More benign lesions were excised in the incidental group (20.2%, 21/104)—representing 3.3% (21/632) of all incidental nodules evaluated—than in the screening group (4%, 1/25) (P = .038). Operative mortality was zero. Among 99 patients with primary lung cancer, 87% (screening) and 86.8% (incidental) were pathologic stage Ia. Complete follow-up was available in 725 of 747 (97%), and no patient developed progressive disease. Disease-free survival at 5 years was 74.9% (incidental) and 89.3% (screening) (P = .48). Conclusions A unique multidisciplinary PNLCSC for incidental and lung cancer screening–detected nodules with individualized risk assessment reliably identifies primary and metastatic tumors while exposing few patients to diagnostic excision for benign disease. Longer-term outcomes, strategies to limit radiation exposure, and cost control need further study.

Background: Tracheal substitutes remain an active area of research. For rare patients with large or complex defects that cannot be repaired primarily, replacement of the airway may represent the only treatment option. The present systematic review aims to assess the clinical successes and setbacks of current methods of airway replacement. Methods: Systematic review using Medline and PubMed from 01 January 2000 to 01 October 2017 focusing on clinical translation of circumferential or near circumferential (>270°) tracheal substitutes. Studies were identified using key phrases including terms such as “tracheal replacement”, “tracheal regeneration”, “tracheal transplant”, “tracheal tissue engineering”, and “tracheal substitution”. Animal or non-clinical studies were excluded. Reviews were included if they contained clinical updates. Results: Twenty-one studies were included in assessment comprising a mix of case reports, case studies, and a single review with clinical updates on prior studies. Since 2001, 41 patients have undergone a reported circumferential or near circumferential tracheal substitution through four underlying methodologies including allotransplantation, autologous tissue reconstruction, bioprosthetic reconstruction, and tissue engineered reconstruction. Each modality has unique advantages and disadvantages with varying success in clinical application. Conclusions: The need for tracheal substitution remains a difficult clinical problem without an ideal prosthetic or graft material. While various modalities have had limited clinical success, further laboratory work is necessary before tracheal substitutes can become widely adopted, especially in the case of tissue engineered conduits, which have been setback by premature clinical translation.

Objectives Complete resection of neoplasms involving the carina are technically challenging and have high operative morbidity and mortality. This study examines the last 2 decades of clinical experience at our institution. Methods Medical records were retrospectively reviewed between 1997 and 2017 to identify all patients who underwent carinal resection. Primary outcome measures include risk factors for complications and overall survival. Results In total, 45 carinal resections were performed with a median follow-up of 3.4 years (interquartile range 0.8-8.5). Procedures included 21 neocarinal reconstructions (48%), 14 right carinal pneumonectomies (30%), 9 left carinal pneumonectomies (20%), and 1 carinal plus lobar resection (2%). Age ranged from 27 to 74 years, and 23 of 45 patients were female. Eight received neoadjuvant chemotherapy and 6 preoperative radiation. Extracorporeal membrane oxygenation and cardiopulmonary bypass were intraoperatively used for 4 patients with no mortality. Four patients underwent superior vena cava resection and reconstruction. Anastomotic complications occurred in 5 patients, all of which were managed conservatively: 1 required stent placement and a second underwent hyperbaric oxygen therapy. Postoperative events were observed in 26 patients (58%), including pneumonia (n = 11), blood transfusion (n = 8), and atrial arrhythmias (n = 8). More serious complications, such as acute respiratory distress syndrome, occurred in 3 patients. Postoperative events were most closely associated with pulmonary resection (P = .040). There were 3 deaths, yielding an overall operative 30- and 90-day mortality of 6.8% and 7%, respectively. Conclusions Despite advances in perioperative management, carinal resection poses challenges for both patient and surgeon. Preoperative chemotherapy, radiation, and concomitant pulmonary resection were associated with increased risk of complications. Patient selection and meticulous surgical technique contribute to reduction in morbidity and mortality.

Aerodigestive defects involving the trachea, bronchi and esophagus are a result of prolonged intubation, operative complications, congenital defects, trauma, radiation and neoplastic disease. The vast majority of these defects may be repaired primarily. Rarely, due the size of the defect, underlying complexity, or unfavorable patient characteristics, primary repair is not possible. One alternative to primary repair is bioprosthetic repair. Materials such as acellular dermal matrix and aortic homograft have been used in a variety of applications, including closure of tracheal, bronchial and esophageal defects. Herein, we review the use of bioprosthetics in the repair of aerodigestive defects, along with the unique advantages and disadvantages of these repairs.

Bioengineering of viable, functional, and implantable human lung grafts on porcine matrix.Implantable bioartificial organ grafts could revolutionize transplant surgery. To date, several milestones toward that goal have been achieved in rodent models. To make bioengineered organ grafts clinically relevant, scaling to human cells and graft size are the next steps.We seeded porcine decellularized lung scaffolds with human airway epithelial progenitor cells derived from rejected donor lungs, and banked human umbilical vein endothelial cells. We subsequently enabled tissue formation in whole organ culture. The resulting grafts were then either analyzed in vitro (n = 15) or transplanted into porcine recipients in vivo (n = 3).By repopulating porcine extracellular matrix scaffolds with human endothelial cells, we generated pulmonary vasculature with mature endothelial lining and sufficient anti-thrombotic function to enable blood perfusion. By repopulating the epithelial surface with human epithelial progenitor cells, we created a living, functioning gas exchange graft. After surgical implantation, the bioengineered lung grafts were able to withstand physiological blood flow from the recipient's pulmonary circulation, and exchanged gases upon ventilation during the 1-hour observation.Engineering and transplantation of viable lung grafts based on decellularized porcine lung scaffolds and human endothelial and epithelial cells is technically feasible. Further graft maturation will be necessary to enable higher-level functions such as mucociliary clearance, and ventilation-perfusion matching.

Background Organ engineering is a theoretical alternative to allotransplantation for end-stage organ failure. Whole-organ scaffolds can be created by detergent perfusion via the native vasculature, generating an acellular matrix suitable for recellularization with selected cell types. We aimed to up-scale this process, generating biocompatible scaffolds of a clinically relevant scale. Methods Rat, porcine, and human lungs were decellularized by detergent perfusion at constant pressures. Collagen, elastin, and glycosaminoglycan content of scaffolds were quantified by colorimetric assays. Proteomic analysis was performed by microcapillary liquid chromatography tandem mass spectrometry. Extracellular matrix (ECM) slices were cultured with human umbilical vein endothelial cells (HUVEC), small airway epithelial cells (SAEC), or pulmonary alveolar epithelial cells (PAECs) and evaluated by time-lapse live cell microscopy and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. Whole-organ culture was maintained under constant-pressure media perfusion after seeding with PAECs. Results Rat lungs were decellularized using: (1) sodium dodecyl sulfate (SDS), (2) sodium deoxycholate (SDC), or (3) 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). Resulting scaffolds showed comparable loss of DNA but greatest preservation of ECM components in SDS-decellularized lungs. Porcine ( n = 10) and human ( n = 7) lungs required increased SDS concentration, perfusion pressures, and time to achieve decellularization as determined by loss of DNA, with preservation of intact matrix composition and lung architecture. Proteomic analysis of human decellularized lungs further confirmed ECM preservation. Recellularization experiments confirmed scaffold biocompatibility when cultured with mature cell phenotypes and scaffold integrity for the duration of biomimetic culture. Conclusions SDS-based perfusion decellularization can be applied to whole porcine and human lungs to generate biocompatible organ scaffolds with preserved ECM composition and architecture.

Approximately 100,000 individuals in the United States currently await kidney transplantation, and 400,000 individuals live with end-stage kidney disease requiring hemodialysis. The creation of a transplantable graft to permanently replace kidney function would address donor organ shortage and the morbidity associated with immunosuppression. Such a bioengineered graft must have the kidney's architecture and function and permit perfusion, filtration, secretion, absorption and drainage of urine. We decellularized rat, porcine and human kidneys by detergent perfusion, yielding acellular scaffolds with vascular, cortical and medullary architecture, a collecting system and ureters. To regenerate functional tissue, we seeded rat kidney scaffolds with epithelial and endothelial cells and perfused these cell-seeded constructs in a whole-organ bioreactor. The resulting grafts produced rudimentary urine in vitro when perfused through their intrinsic vascular bed. When transplanted in an orthotopic position in rat, the grafts were perfused by the recipient's circulation and produced urine through the ureteral conduit in vivo.

To explore how the 2 most important components of surgical performance--speed and accuracy-are influenced by different forms of stress and what the impact of music is on these factors.On the basis of a recently published pilot study on surgical experts, we designed an experiment examining the effects of auditory stress, mental stress, and music on surgical performance and learning and then correlated the data psychometric measures to the role of music in a novice surgeon's life.Thirty-one surgeons were recruited for a crossover study. Surgeons were randomized to 4 simple standardized tasks to be performed on the SurgicalSIM VR laparoscopic simulator (Medical Education Technologies, Inc, Sarasota, FL), allowing exact tracking of speed and accuracy. Tasks were performed under a variety of conditions, including silence, dichotic music (auditory stress), defined classical music (auditory relaxation), and mental loading (mental arithmetic tasks). Tasks were performed twice to test for memory consolidation and to accommodate for baseline variability. Performance was correlated to the brief Musical Experience Questionnaire (MEQ).Mental loading influences performance with respect to accuracy, speed, and recall more negatively than does auditory stress. Defined classical music might lead to minimally worse performance initially but leads to significantly improved memory consolidation. Furthermore, psychologic testing of the volunteers suggests that surgeons with greater musical commitment, measured by the MEQ, perform worse under the mental loading condition.Mental distraction and auditory stress negatively affect specific components of surgical learning and performance. If used appropriately, classical music may positively affect surgical memory consolidation. It also may be possible to predict surgeons' performance and learning under stress through psychological tests on the role of music in a surgeon's life. Further investigation is necessary to determine the cognitive processes behind these correlations.

End-stage lung disease is a major health care challenge. Lung transplantation remains the definitive treatment, yet rejection and donor organ shortage limit its broader clinical impact. Engineering bioartificial lung grafts from patient-derived cells could theoretically lead to alternative treatment strategies. Although many challenges on the way to clinical application remain, important early milestones toward translation have been met. Key endodermal progenitors can be derived from patients and expanded in vitro. Advanced culture conditions facilitate the formation of three-dimensional functional tissues from lineage-committed cells. Bioartificial grafts that provide gas exchange have been generated and transplanted into animal models. Looking ahead, current challenges in bioartificial lung engineering include creation of ideal scaffold materials, differentiation and expansion of lung-specific cell populations and full maturation of engineered constructs to provide graft longevity after implantation in vivo. A multidisciplinary collaborative effort will not only bring us closer to the ultimate goal of engineering patient-derived lung grafts, but also generate a series of clinically valuable translational milestones such as airway grafts and disease models. This review summarizes achievements to date, current challenges and ongoing research in bioartificial lung engineering.

Background Decellularized whole-organ scaffolds show great potential in cancer research. They have been used in the biomimetic three-dimensional (3D) culture of non-small cell lung cancer cells, allowing the study of unique aspects of lung cancer biology. However, there are no reproducible assays capable of directly monitoring processes involved in cancer progression within such scaffolds. Methods The human adenocarcinoma cell lines H358, PC9, and SW1573 were subjected to biomimetic 3D culture within decellularized lung scaffolds. A resazurin-based reagent was perfused through the scaffold to determine cell viability over the culture period and in response to treatment with cisplatin or erlotinib. Results The resazurin reduction perfusion assay detected a progressive increase in the reduction of resazurin over time for all cell lines cultured within decellularized lung scaffolds, translating into incremental cell populations. Also, it detected a positive cytotoxic effect in H358- and PC9-seeded scaffolds after treatment with cisplatin, and in PC9-seeded scaffolds after treatment with erlotinib. Moreover, it identified relative resistance to erlotinib in H358- and SW1573-seeded scaffolds. Results from this assay correlated with histopathology, expression of caspase 3, and activity of epidermal growth factor receptor signaling. Conclusions The methods described here for the monitoring of lung cancer cell viability under biomimetic 3D culture conditions within decellularized lung scaffolds permit the study of cancer cell proliferation, the evaluation of responses to therapeutic interventions, and the determination of relative chemo-sensitivities.

Background Idiopathic subglottic stenosis is a rare inflammatory condition affecting the subglottic larynx. We have treated 263 patients (only 2 were male) with this condition. The purpose of this study is to determine factors affecting outcome and predisposing to complications. Methods Information was gathered from chart reviews, surveys, and a prospective database. Results Median time from diagnosis to surgery was 24 months. Antinuclear antibodies when measured were positive in 76 patients (47%). Prior tracheal procedures were done in 58 patients (22%), and 184 patients (70%) had prior endoscopic procedures. Resection of the posterior cricoid mucosa with tracheal membranous wall flap was done in 150 patients (57%). Tailored cricoplasty was performed in 105 patients (40%). Extubation in the operating room was achieved in 247 patients (94%). Steroid therapy for edema was required in 63 patients (24%). Anastomotic complications occurred in 30 patients, 17 granulations and 7 subcutaneous air. Twenty-three patients (8.7%) have recurrence (14 mild, 9 recalcitrant) requiring dilation. Risk factors for anastomotic complications and recurrence were edema requiring steroids, use of mitomycin C, and prior tracheostomy, stents, and vocal cord involvement. Follow-up was available for 227 patients. Follow-up survey of 180 patients revealed, on a 10-point scale, effectiveness 9.4, satisfaction 9.4, and symptom improvement 9.4. A normal voice was present in 82 patients (45%); 96 patients (54%) had change in voice; and 121 patients (67%) had difficulty projecting their voice. Conclusions Single-stage reconstructive surgery resulted in 96% good-to-excellent results. Recalcitrant stenosis developed in 4% of patients. Stents, postoperative edema, mitomycin use, and vocal cord involvement are risks for recurrence. Recurrence was related to reactivation of disease in 14 patients and to technical problems in 6 patients.

The loss of an extremity is a disastrous injury with tremendous impact on a patient's life. Current mechanical prostheses are technically highly sophisticated, but only partially replace physiologic function and aesthetic appearance. As a biologic alternative, approximately 70 patients have undergone allogeneic hand transplantation to date worldwide. While outcomes are favorable, risks and side effects of transplantation and long-term immunosuppression pose a significant ethical dilemma. An autologous, bio-artificial graft based on native extracellular matrix and patient derived cells could be produced on demand and would not require immunosuppression after transplantation. To create such a graft, we decellularized rat and primate forearms by detergent perfusion and yielded acellular scaffolds with preserved composite architecture. We then repopulated muscle and vasculature with cells of appropriate phenotypes, and matured the composite tissue in a perfusion bioreactor under electrical stimulation in vitro. After confirmation of composite tissue formation, we transplanted the resulting bio-composite grafts to confirm perfusion in vivo.

Cardiovascular disease is a major public health challenge in the western world. Mortality of acute events has improved, but more patients develop HF--a condition affecting up to 22 million people worldwide. Cell transplantation is the first therapy to attempt replacement of lost cardiomyocytes and vasculature to restore lost contractile function. Since the first reported functional repair after injection of autologous skeletal myoblasts into the injured heart in 1998, a variety of cell types have been proposed for transplantation in different stages of cardiovascular disease. Fifteen years of preclinical research and the rapid move into clinical studies have left us with promising results and a better understanding of cells as a potential clinical tool. Cell-based cardiac repair has been the first step, but cardiac regeneration remains the more ambitious goal. Promising new cell types and the rapidly evolving concept of adult stem and progenitor cell fate may enable us to move towards regenerating viable and functional myocardium. Meeting a multidisciplinary consensus will be required to translate these findings into safe and applicable clinical tools.

Cardiac cell transplantation offers new opportunities as a potent therapeutic tool to improve left ventricular (LV) function and reverse postinfarction remodeling in ischemic heart disease. Skeletal myoblasts (SKMBs) engraft within infarcted myocardium, form myotubes, induce angiogenesis, and improve both diastolic and systolic LV function. 1 Bone marrow‐derived mononuclear cells (BM-MNCs) likewise engraft, increase angiogenesis, and improve myocardial perfusion. 2 Both cell types have moved to clinical testing, and preclinical studies suggest that they could have synergistic functional benefits that argue for combined transplantation. 3,4 Intramyocardial injections are currently performed either percutaneously through an endoventricular or transvenous approach or surgically through a thoracotomy or sternotomy. We recently reported a video-assisted thoracoscopic technique to reduce invasiveness and perioperative risk of surgical cell delivery that was tested in uninjured swine hearts. 5 In the setting of heart failure (HF), mechanical manipulation of the left ventricle both by means of stabilization and cell injection must be minimized to prevent hemodynamic compromise, arrhythmia, and ventricular perforation. Robotically assisted cardiac surgery combines the advantages of minimal invasiveness and thoracoscopic access but adds a 3-dimensional view and 7 degrees of freedom that requires less cardiac manipulation than with the 2-dimensional view and limited freedom of motion of video-assisted thoracoscopic surgery. 6 We therefore propose a robot-assisted, beating-heart cell transplantation technique for use in severe HF to increase safety, optimize targeting, and reduce procedural time.

Heart failure (HF) affects a rapidly growing population of patients. Despite improvements in the understanding and therapy of many stages of cardiovascular disease, there has been little progress in treating HF. In the late-stage disease, current options are cardiac transplantation and mechanical support--options that are limited to a small patient collective. The ischemically injured failing heart lacks contractile myocardium, functional vasculature, and electrical integrity, which has made treatment of the underlying injury untenable in the past. Restoring all of these components seems an overwhelming challenge. Yet, the concept of cell therapy--tissue repair by transplantation of stem and progenitor cells--has opened new potential options for patients with heart failure. Skeletal myoblasts, bone marrow, and blood-derived stem cells have all shown considerable myogenic and angiogenic potential in vitro and have rapidly moved from bench to bedside. A number of nonrandomized, non-placebo-controlled safety and feasibility studies have been reported and now double-blinded randomized controlled trials are underway. Despite this rapid clinical pace, the exact mechanisms underlying the functional benefits of different cell types are not well understood. Instead, multiple similar mechanism have been ascribed to virtually every cell type. Thus, while the field is exciting and offers unheralded promise to treat patients with CVD, we must proceed with due diligence and caution. Only a deep understanding of the benefits versus the risks, and the mechanisms involved in cell-mediated cardiac repair, will allow us to design clinically valuable tools and fulfill the potential of this exciting 21st century approach to treating cardiovascular disease.

Objective: Recent progress in the field of cellular cardiomyoplasty has opened new prospects for the treatment of ischemic heart disease and currently moves from bench to bedside. The aim of the present study was to develop a novel cell delivery technique, reducing target tissue damage and improving cell dispersion and engraftment. Methods: In 30 male Fischer F344 rats an infarction of the left ventricle was generated by ligation of the left anterior descendent artery. Seven days after infarction, either 15 microdepots of 10 ml myoblast cell suspension (microdepot group) or culture medium (control group) were injected into the infarcted region using an automatic pressure injection device, or three depots of 50 ml myoblast cell suspension (macrodepot group) were injected using the standard surgical technique. Echocardiography was performed in all rats before and 6 weeks after cell injection. In all groups the perioperative mortality was below 20%. Six weeks after cell transplantation, a significant improvement of ejection fraction was seen in both myoblast treated groups compared to controls (macrodepot, microdepot, control; 53.7G11.9, 70.7G2.0, 39.1G6.4; PZ0.026, P!0.001). The microdepot group showed a more decent improvement than the macrodepot group (70.7G2.0 vs. 53.7G11.9, PZ0.013). In both treated groups, grafted myoblasts differentiated into multinucleated myotubes within host myocardium, however, the engraftment pattern was different and angiogenesis was enhanced in the microdepot group. Conclusions: Intramyocardial multisite pressure injection allows the safe and reliable transplantation of several myoblast microdepots into an infarcted myocardium and improves the efficacy of myoblast transplantation compared to the standard technique. Q 2005 Elsevier B.V. All rights reserved.

Objective: Rapamycin is an immunosuppressive agent with marked antiproliferative properties and is effective in reducing in stent restenosis and vein graft neointimal hyperplasia. Apoptosis is one mechanism counterbalancing cellular proliferation. We therefore investigated the role of apoptosis in rapamycin treated vein grafts in a mouse model. Methods: C57BL6J mice underwent interposition of the inferior vena cava from isogenic donor mice into the common carotid artery using a cuff technique. In the treatment group 200 mg of rapamycin were applied locally in pluronic gel. The control group did not receive local treatment. Vein grafts were harvested at 4 weeks postoperatively and underwent morphometric analysis as well as immunohistochemical analysis for apoptosis (TUNEL). Results: In grafted veins without treatment (controls) neointimal thickness was 50 (12–58) mm at 4 weeks postoperatively. In 200 mg rapamycin treated grafts the neointimal thickness was 17 (5–55) mm. Rapamycin treated vein grafts showed a significantly increased rate of apoptosis in the adventitia as compared with controls (PZ0.032). In the neointima the apoptosis rate was lower in both groups with no significant difference between rapamycin treated grafts and controls. Conclusion: We conclude that treatment of experimental vein grafts with rapamycin is associated with an increased apoptosis rate in the vascular wall and a trend towards reduction of neointimal hyperplasia. These results suggest that apoptosis may be a beneficial antiproliferative component for the treatment of vein graft disease. q 2004 Elsevier B.V. All rights reserved.

The primary treatment for end-stage lung disease is lung transplantation. However, donor organ shortage remains a major barrier for many patients. In recent years, techniques for maintaining lungs ex vivo for evaluation and short-term (

Patients suffering from end-stage organ failure requiring organ transplantation face donor organ shortage and adverse effect of chronic immunosuppression. Recent progress in the field of organ bioengineering based on decellularized organ scaffolds and patient-derived cells holds great promise to address these issues.Perfusion-decellularization is the most consistent method to obtain decellularized whole-organ scaffolds to serve as a platform for organ bioengineering. Important advances have occurred in organ bioengineering using decellularized scaffolds in small animal models. However, the function exhibited by bioengineered organs has been rudimentary. Pluripotent stem cells seem to hold promise as the ideal regenerative cells to be used with this approach but the techniques to effectively and reliably manipulate their fate are still to be discovered. Finally, this technology needs to be scaled up to human size to be of clinical relevance.The search for alternatives to allogeneic organ transplantation continues. Important milestones have been achieved in organ bioengineering with the use of decellularized scaffolds. However, many challenges remain on the way to producing an autologous, fully functional organ that can be transplanted similar to a donor organ.

Background Whole-lung scaffolds can be created by perfusion decellularization of cadaveric donor lungs. The resulting matrices can then be recellularized to regenerate functional organs. This study evaluated the capacity of acellular lung scaffolds to support recellularization with lung progenitors derived from human induced pluripotent stem cells (iPSCs). Methods Whole rat and human lungs were decellularized by constant-pressure perfusion with 0.1% sodium dodecyl sulfate solution. Resulting lung scaffolds were cryosectioned into slices or left intact. Human iPSCs were differentiated to definitive endoderm, anteriorized to a foregut fate, and then ventralized to a population expressing NK2 homeobox 1 (Nkx2.1). Cells were seeded onto slices and whole lungs, which were maintained under constant perfusion biomimetic culture. Lineage specification was assessed by quantitative polymerase chain reaction and immunofluorescent staining. Regenerated left lungs were transplanted in an orthotopic position. Results Activin-A treatment, followed by transforming growth factor-β inhibition, induced differentiation of human iPSCs to anterior foregut endoderm as confirmed by forkhead box protein A2 (FOXA2), SRY (Sex Determining Region Y)-Box 17 (SOX17), and SOX2 expression. Cells cultured on decellularized lung slices demonstrated proliferation and lineage commitment after 5 days. Cells expressing Nkx2.1 were identified at 40% to 60% efficiency. Within whole-lung scaffolds and under perfusion culture, cells further upregulated Nkx2.1 expression. After orthotopic transplantation, grafts were perfused and ventilated by host vasculature and airways. Conclusions Decellularized lung matrix supports the culture and lineage commitment of human iPSC-derived lung progenitor cells. Whole-organ scaffolds and biomimetic culture enable coseeding of iPSC-derived endothelial and epithelial progenitors and enhance early lung fate. Orthotopic transplantation may enable further in vivo graft maturation.

Background Extracellular matrix allows lung cancer to form its shape and grow. Recent studies on organ reengineering for orthotopic transplantation have provided a new avenue for isolating purified native matrix to use for growing cells. Whether human lung cancer cells grown in a decellularized rat lung matrix would create perfusable human lung cancer nodules was tested. Methods Rat lungs were harvested and native cells were removed using sodium dodecyl sulfate and Triton X-100 in a decellularization chamber to create a decellularized rat lung matrix. Human A549, H460, or H1299 lung cancer cells were placed into the decellularized rat lung matrix and grown in a customized bioreactor with perfusion of oxygenated media for 7 to 14 days. Results Decellularized rat lung matrix showed preservation of matrix architecture devoid of all rat cells. All three human lung cancer cell lines grown in the bioreactor developed tumor nodules with intact vasculature. Moreover, the lung cancer cells developed a pattern of growth similar to the original human lung cancer. Conclusions Overall, this study shows that human lung cancer cells form perfusable tumor nodules in a customized bioreactor on a decellularized rat lung matrix created by a customized decellularization chamber. The lung cancer cells grown in the matrix had features similar to the original human lung cancer. This ex vivo model can be used potentially to gain a deeper understanding of the biologic processes involved in human lung cancer.

Background More than 11 million Americans live with chronic lung disease; in search for an alternative to donor organs, we attempted to regenerate lungs based on perfusion decellularized lung scaffolds that can be transplanted similar to a donor organ. Methods Cadaveric rat lungs were decellularized by detergent perfusion. Resulting scaffolds were mounted in bioreactors and seeded with endothelial and fetal lung cells. Biomimetic organ culture was maintained for 7 days. Resulting bioartificial left lungs were transplanted in orthotopic position after left pneumonectomy in rats. Cadaveric left lung transplants and pneumonectomies served as controls. Blood gas analyses, compliance testing, and fluoroscopies were performed on postoperative days 1, 7, and 14. Lungs were removed for final analysis on day 14. Results Perfusion decellularization of cadaveric lungs yielded acellular scaffolds with intact architecture and matrix composition. Alveolar volumes, number, and size were comparable in bioartificial and native lungs, as were gas exchange, vital capacity and compliance in vitro. After using improved graft preservation and postoperative weaning protocols, animals could be fully recovered, and bioartificial lung constructs provided oxygenation as long as 7 days at levels comparable to cadaveric lung transplants. Compliance, gas exchange, and radiographic appearance gradually declined over the subsequent 7 days owing to progressive graft consolidation and inflammation. Conclusions Perfusion decellularization of cadaveric lungs yields intact scaffolds that can be seeded with cells to generate bioartificial lung grafts. After orthotopic transplantation, grafts are perfused by the recipient's circulation, ventilated through the recipient's airway and provide gas exchange in vivo for 7 days.

There are few data to predict the benefit of pulmonary metastasectomy in patients with extrathoracic sarcoma. This study analyzes prognostic factors associated with improved outcomes.Between June 2002 and December 2008, 97 patients underwent pulmonary resection for metastatic sarcoma at Massachusetts General Hospital. Eight patients were excluded because of lack of follow-up data. Analysis was performed using Kaplan-Meier estimates of survival, log-rank test, and multivariate Cox model.Overall 5-year survival for the cohort was 50.1%. Patients who had multiple operations for recurrent pulmonary metastases had better 5-year survival compared with patients who had a single operation (69 versus 41%; p = 0.017). Median disease- free survival (DFS) for the reoperation group was 12.9 months compared with 9.1 months for the single-operation group (p0.028). Patients with a disease-free interval (DFI) greater than 12 months from detection of primary sarcoma to pulmonary metastasectomy had improved survival compared with those whose DFI was less than 12 months (p0.0001). Patients with bilateral metastasectomy had lower 5-year survival compared with metastasectomy for unilateral disease (22% versus 68% ;p0.0001). Two or more metastases were associated with poorer outcome compared with a single metastasis (p = 0.0007). A positive resection margin portended worse survival compared with a negative resection margin (p = 0.004). Patients with lesions larger than 3 cm had decreased survival compared with patients with lesions smaller than 3 cm (p = 0.017) with no difference in median DFS. Histologic type, grade of tumor, and use of chemotherapy had no effect on survival. Multivariate analysis showed that patients with a DFI greater than 12 months (p = 0.001), single-sided metastasis (p = 0.001), negative margins (p = 0.002), and multiple operations (p = 0.018) had better survival.Pulmonary metastasectomy for sarcoma can be associated with prolonged survival. Tumor resectability, DFI, number of metastases, and laterality are important factors in determining patient selection for curative surgical intervention. Repeated pulmonary metastasectomy in select patients may improve survival despite recurrent disease.

About 2,000 patients now await a donor lung in the United States. Worldwide, 50 million individuals are living with end-stage lung disease. Creation of a bioartificial lung requires engineering of viable lung architecture enabling ventilation, perfusion and gas exchange. We decellularized lungs by detergent perfusion and yielded scaffolds with acellular vasculature, airways and alveoli. To regenerate gas exchange tissue, we seeded scaffolds with epithelial and endothelial cells. To establish function, we perfused and ventilated cell-seeded constructs in a bioreactor simulating the physiologic environment of developing lung. By day 5, constructs could be perfused with blood and ventilated using physiologic pressures, and they generated gas exchange comparable to that of isolated native lungs. To show in vivo function, we transplanted regenerated lungs into orthotopic position. After transplantation, constructs were perfused by the recipient's circulation and ventilated by means of the recipient's airway and respiratory muscles, and they provided gas exchange in vivo for up to 6 h after extubation.

Objectives Cellular cardiomyoplasty using skeletal myoblasts or angiopoietic progenitor cells offers a promising approach for the treatment of ischemic heart failure. Although several studies have shown encouraging results in acute myocardial infarction, the efficacy of cell therapy using skeletal myoblasts and angiopoietic progenitor cells in chronic ischemic heart disease remains undetermined. Methods Ischemic heart failure was induced by left anterior descending coronary artery ligation in nude rats: (1) Culture medium, (2) homologous skeletal myoblasts (SM), (3) human AC-133+ cells (SC), and (4) both skeletal myoblasts and AC-133+ cells (Comb) were injected in the infarct (SM) and peri-infarct area (SC) 4 weeks after infarction. Assessment of myocardial function included echocardiography 4 weeks after cell delivery. Histology was based on quantification of myocardial fibrosis, apoptosis, and capillary density. Results Left ventricular dilatation was attenuated and ejection fraction improved significantly after cell transplantation (SM: 59.4% ± 8.8%, SC: 60.3% ± 6.6%, Comb: 68.2% ± 5.6% vs control: 41.5% ± 7.4%, P = .0013). Quantification of scar tissue showed a significant reduction of infarct area in cell-treated animals (SM: 22.3% ± 9.1%, SC: 19.8% ± 7.6%, Comb: 13.2% ± 5.8% vs controls: 36.5% ± 8.2%, P = .008). Improvement of myocardial function was associated with reduced apoptotic index (SM: 3.2% ± 0.9%, SC: 3.1% ± 0.6%, Comb: 1.8% ± 0.8% vs controls: 10.3% ± 1.6%, P = .0002) and increased vascular density (SM: 5.2 ± 1.2, SC: 8.3 ± 1.8, Comb: 12.3 ± 2.3, controls: 1.9 ± 0.3, all capillary vessels/high-power field, P = .007) in animals after cellular cardiomyoplasty. Conclusions Combined transplantation of skeletal myoblasts and angiopoietic progenitor cells results in ventricular function improvement, reduction of scar size and myocardial apoptosis, and increased neoangiogenesis in chronic ischemia. Clinical studies are warranted to prove this new therapeutic concept.

Purpose Organ engineering is a theoretical therapy for organ failure. Whole organ matrices can be created by detergent perfusion, generating acellular scaffolds with the capacity for recellularization. This study aimed to up-scale this technology to clinically relevant porcine and human lungs, and to test their recellularization potential in biomimetic culture. Methods and Materials Rat, pig, and human lungs were perfused with detergent via the pulmonary artery at constant pressures, followed by washing. DNA was quantified by PicoGreen. Residual SDS was quantified by Stains-All assay. Soluble collagen, elastin, and glycosaminoglycans were quantified by colourimetric assays. Proteomic analysis by mass spectrometry (LC-MS/MS) generated spectral counts as a measure of abundance. Perfusion recellularization experiments of human lungs used standard organ culture techniques derived from rodent protocols. Results Rat lungs decellularized using (1) Sodium Dodecyl Sulfate (SDS), (2) Sodium deoxycholate, or (3) CHAPS showed loss of DNA but greatest preservation of ECM in SDS decellularized lungs. Histology and proteomics also confirmed greater matrix preservation in SDS lungs. The SDS-based decellularization protocol was up-scaled to porcine (n=7) and human (n=3) lungs with greater SDS concentration and perfusion pressures, and extended decellularization time. Removal of residual DNA and SDS was confirmed. Analysis of 10 areas from each decellularized lung showed intact ECM and lung architecture. Proteomics of human decellularized lungs further demonstrated matrix preservation. Recellularization of isolated lobar scaffolds used endothelial (HUVEC) and lung epithelial (SAEC) lines delivered to the appropriate organ compartment. Throughout biomimetic organ culture matrix integrity was maintained, while cell retention was observed by H&E and DAPI. Conclusions SDS decellularization can generate organ scaffolds with preserved ECM and architecture in whole porcine and human lungs. The results confirm clinical scale lung scaffolds can support recellularization for organ regeneration.

Background Robotic surgical systems are most effective for operations in areas that are small and difficult to reach. Ideal indications for this new technology have yet to be established. The esophagus possesses attributes that are interesting for general thoracic robotic surgeons. Methods Robotic-assisted thoracoscopic surgery (RATS) using the da Vinci system (Intuitive Surgical, Inc, Mountain View, CA) was performed in six patients with esophageal tumors. This comprised the dissection of the intrathoracic esophagus including lymph node dissection in four patients suffering from esophageal cancer and the extirpation of a benign lesion (one leiomyoma and one foregut cyst) in the remaining two patients. Results All procedures were completed successfully with the robot. The median overall operating time was 173 (160–190) minutes in the oncologic cases and 121 minutes in the benign cases, including the robotic act of 147 (135–160) minutes and 94 minutes, respectively. There were no intraoperative complications. One patient had to undergo a redo thoracoscopy because of a persistent lymph fistula. One cancer patient died after 12 months due to tumor progression and another patient had to be stented due to local tumor recurrence 19 months postoperatively. Conclusions This first small series of various esophageal pathologies treated by robotic-assisted thoracoscopic surgery supports the impression that the esophagus is an ideal organ for a robotic approach. The potential of the da Vinci system, especially for oncologic indications, remains to be proven in future clinical trials.

Objectives: To prove whether intramyocardial transplantation of combined skeletal myoblasts (SM) and mononuclear bone marrow stem cells is superior to the isolated transplantation of these cell types after myocardial infarction in rats. Methods: In 67 male Fischer rats myocardial infarction was induced by direct ligature of the LAD. Seven days postinfarction baseline echocardiography and intramyocardial cell transplantation were performed. Via lateral thoracotomy 200 ml containing either 10 7 SMs or 10 7 bone marrow-derived mononuclear cells (BM-MNC) or a combination of 5 £ 10 6 of both cell types (MB) were injected in 10 –15 sites in and around the infarct zone. In controls (C) 200 ml of cell-free medium were injected in the same manner. Before injection both cell types were stained using a fluorescent cell linker kit (PKH, Sigma). In addition, SMs were transfected with green fluorescent protein. Nine weeks postinfarction follow-up echocardiography was performed and animals were sacrificed for further analysis. Results: At baseline echocardiography there was no difference in left ventricular ejection fraction (LVEF; C, SM, BM-MNC, MB: 60.1 ^ 3.2, 53.3 ^ 10.2, 53.1 ^ 8.7, 49 ^ 9.0%) and left ventricular end diastolic diameter (LVEDD; C, SM, BM-MNC, MB: 6.5 ^ 0.8, 5.17 ^ 0.8, 5.77 ^ 1.4, 6.25 ^ 0.8 mm) between the different therapeutic groups. Eight weeks after cell transplantation LVEDD was significantly increased in all animals except those that received a combination of myoblasts and bone marrow stem cells (MB; C, SM, BM-MNC, MB: 7.7 ^ 0.6 mm, P ¼ 0:001; 7.7 ^ 1.5 mm, P , 0:001; 7.7 ^ 1.1 mm, P ¼ 0:005; 6.6 ^ 1.7 mm, P ¼ 0:397). At the same time LVEF decreased significantly in the control group (C), stayed unchanged in animals that received bone marrow stem cells (BM-MNC) and increased in animals that received myoblasts (SM) and a combination of both cell types (MB; C, SM, BM-MNC, MB: 45.3 ^ 7.0%, P ¼ 0:05; 63.9 ^ 15.4%, P ¼ 0:044; 54.3 ^ 6.3%, P ¼ 0:607; 63.0 ^ 11.5%, P ¼ 0:039). Conclusions: The present data show that the concept of combining SMs with bone marrow-derived stem cells may be of clinical relevance by merging the beneficial effects of each cell line and potentially reducing the required cell quantity. Further studies are required to identify the exact mechanisms underlying this synergy and to allow full exploitation of its therapeutic potential. q 2004 Elsevier B.V. All rights reserved.