The nodule in the emphysematous lung: an appeal for surgery in a lung volume reduction concept.

Background: Emphysema patients, who are candidates for lung volume reduction surgery (LVRS) usually present with an extensive smoking history and thus have an increased risk for lung. The incidence of pulmonary nodules in emphysematous lungs is high. We therefore aimed to analyse the incidence and histological findings of pulmonary nodules in our LVRS program. Methods: We conducted a retrospective review of all patients who underwent LVRS between 2016 and 2018. Data concerning preoperative workup, 30 days mortality and histopathological findings analysed. Results: Between 2016 and 2018, LVRS was performed in 66 patients. In 18 (27%) a nodule was found in the preoperative computed tomography (CT) scan. Histological findings revealed in two cases squamous cell lung cancer. In two other cases, histopathological findings revealed an anthracotic intrapulmonary lymph node. In eight cases, a tuberculoma was found with a positive culture in one case. The other six histopathological findings were hamartoma, granuloma or sequelae of pneumonia. Conclusions: Malignancy was found in 11.1% of patients presenting with a nodule in preoperative LVRS workup. The relative risk of lung cancer in emphysema patients is increased and if LVRS criteria are fulfilled surgical resection of a pulmonary nodule is a meaningful way to verify the histology.

Tumour cell PD-L1 expression is prognostic in patients with malignant pleural effusion: the impact of C-reactive protein and immune-checkpoint inhibition.

Malignant pleural effusion (MPE) confers dismal prognosis and has limited treatment options. While immune-checkpoint inhibition (ICI) proved clinical efficacy in a variety of malignancies, data on the prognostic role of PD-L1 in MPE is scarce. We retrospectively studied PD-L1 tumour proportion score and Ki-67 index in pleural biopsies or cytologies from 123 patients (69 lung cancer, 25 mesothelioma, and 29 extrathoracic primary malignancies). Additionally, the impact of C-reactive protein (CRP) and platelet count was also analysed. Median overall survival (OS) after MPE diagnosis was 9 months. Patients with PD-L1 positive tumours (≥1%) had significantly shorter OS than patients with negative PD-L1 status (p = 0.031). CRP and Ki-67 index were also prognostic and remained independent prognosticators after multivariate analysis. Interestingly, Ki-67 index and CRP influenced the prognostic power of PD-L1. Finally, patients receiving ICI tended to have a longer median OS and CRP - but not PD-L1 - was a significant prognosticator in this subgroup. In summary, histological and circulating biomarkers should also be taken into account as potential biomarkers in ICI therapy and they may have an impact on the prognostic power of PD-L1. Our findings might help personalizing immune-checkpoint inhibition for patients with MPE and warrant further prospective validation.

A novel mutation of the folliculin gene causing Birt-Hogg-Dubé syndrome as rare cause for secondary pneumothorax.

The Birt-Hogg-Dubé syndrome is an orphan genetic disease characterized by the development of renal neoplasms, fibrofolliculomas, pulmonary cysts and spontaneous pneumothoraces. Here, we report on the case of a 21-year-old man presenting with a primary event of a persistent spontaneous pneumothorax. Computed tomography images and a positive family history for pneumothoraces led to the suspicion of Birt-Hogg-Dubé syndrome. Genetic testing then confirmed the suspected clinical diagnosis, however with a mutation that has not yet been reported.

Increased lymphangiogenesis in lung metastases from colorectal cancer is associated with early lymph node recurrence and decreased overall survival.

Pulmonary metastasectomy (PM) is an accepted treatment modality in colorectal cancer (CRC) patients with pulmonary tumor spread. Positive intrathoracic lymph nodes at the time of PM are associated with a poor prognosis and 5-year survival rates of <20 %. Increased lymphangiogenesis in pulmonary metastases might represent an initial step for a subsequent lymphangiogenic spreading. We aimed to evaluate the presence of lymphangiogenesis in clinically lymph node negative patients undergoing PM and its impact on outcome parameters. 71 patients who underwent PM for CRC metastases were included in this dual-center study. Tissue specimens of pulmonary metastases and available corresponding primary tumors were assessed by immunohistochemistry for lymphatic microvessel density (LMVD) and lymphovascular invasion (LVI). Results were correlated with clinical outcome parameters. LMVD was 13.9 ± 8.1 and 13.3 ± 8.5 microvessels/field (mean ± SD) in metastases and corresponding primary CRC; LVI was evident in 46.5 and 58.6 % of metastases and corresponding primary CRC, respectively. Samples with high LMVD had a higher likelihood of LVI. LVI was associated with early tumor recurrence in intrathoracic lymph nodes and a decreased overall survival (p < 0.001 and p = 0.029). Herein, we present first evidence in a well-defined patient collective that increased lymphangiogenesis is already present in a subtype of pulmonary metastases of patients staged as N0 at the time of PM. This lymphangiogenic phenotype has a strong impact on patients' prognosis. Our findings may have impact on the post-surgical therapeutic management of CRC patients with pulmonary spreading.

Unexpected lymph node disease in resections for pulmonary metastases.

BACKGROUND: Pulmonary metastasectomy is widely accepted for different malignant diseases. The role of mediastinal lymph node (LN) dissection in these procedures is discussed controversially. We evaluated our results of LN removal at the time of pulmonary metastasectomy with respect to the frequency of unexpected LN disease. METHODS: This was a retrospective analysis of 313 resections performed in 209 patients. Operations were performed in curative intention. Patients with known thoracic LN involvement and those without lymphadenectomy (n = 43) were excluded. Patients were analyzed according the type of LN dissection. Subgroups of different primary cancers were evaluated separately. RESULTS: Sublobar resections were performed in 256 procedures with lymphadenectomy, and 14 patients underwent lobectomy. Patients underwent radical lymphadenectomy (n = 158) or LN sampling (n = 112). The overall incidence of unexpected tumor in LN was 17% (radical lymphadenectomy, 15.8%; sampling, 18.8%). Unexpected LN involvement was found in 17 patients (35.5%) with breast cancer, in 120 (9.2%) with colorectal cancer, and in 53 (20.8%) with renal cell carcinoma. The 5-year survival was 30.2% if LN were tumor negative and 25% if positive (p = 0.19). LN sampling vs radical removal had no significant effect on 5-year survival (23.6% vs 30.9%; p = 0.29). CONCLUSIONS: Dissection of mediastinal LN in resection of lung metastases will reveal unexpected LN involvement in a relevant proportion of patients, in particular in breast and renal cancer. Routine LN dissection appears necessary and may become important for further therapeutic decisions. On the basis of our data, LN sampling seems to be sufficient.

The Ross procedure offers excellent survival compared with mechanical aortic valve replacement in a real-world setting.

OBJECTIVES: The ideal prosthesis for young patients requiring aortic valve replacement has not been defined to date. Although the Ross procedure provides excellent survival, its application is still limited. We compared the long-term survival after the Ross procedure with mechanical aortic valve replacement. METHODS: All consecutive Ross procedures and mechanical aortic valve replacements performed between 1991 and 2008 at a single centre were analysed. Only adult patients between 18 and 50 years of age were included in the study. Survival and valve-related complications were evaluated. Furthermore, survival was compared with the age- and sex-matched Austrian population. RESULTS: A total of 159 Ross patients and 173 mechanical valve patients were included. The cumulative survival for the Ross procedure was significantly better, with survival rates of 96, 94 and 93% at 5, 10 and 15 years, respectively, in comparison to 90, 84 and 75% (P < 0.01) for patients with mechanical valves. A Cox regression analysis including patients' age, gender and valve type revealed age and the type of aortic valve replacement as independent significant factors influencing survival (for age, hazard ratio = 1.1, 95% confidence interval = 1.0-1.1, P = 0.03; and for valve type, hazard ratio = 2.6, 95% confidence interval = 1.2-5.8, P = 0.02). The observed survival was comparable to the expected standard survival for the Ross group but was significantly reduced in the mechanical valve group. CONCLUSIONS: In a real-world setting, the Ross procedure is associated with a long-term survival benefit in young adults in comparison to mechanical aortic valve replacement.

A single-center experience with the ross procedure over 20 years.

BACKGROUND: The Ross procedure offers several potential advantages in a young patient population. The widespread use of the procedure is still limited due to the technical challenge. Pulmonary homograft stenosis and autograft dilatation remain a matter of concern. We present the long-term outcome in a single center with special emphasis on mortality and need for valvular reintervention. METHODS: All patients who received a Ross procedure as freestanding root replacement (modified Yacoub technique) at our institution between 1991 and 2011 were followed. Descriptive statistical methods and Kaplan-Meier analyses were performed. RESULTS: A total of 246 patients (191 males, 55 females) underwent the Ross procedure during the study period. There were 176 adults and 70 pediatric patients with an average age of 36 ± 10 and 10 ± 5 years, respectively. The median follow-up was 10 years. Twelve (4.9%) subjects were lost to follow-up. Early mortality was 1.6%. Overall mortality was comparable with an age and sex matched population for adult patients. The linearized risk for reoperation per patient-year was 0.6% for the autograft and 0.6% for the right ventricular outflow tract, with a mean time to surgery of 6.4 ± 4.9 years. Overall freedom from reintervention was 95% at 5 years, 88% at 10 years, and 81% at 15 years. CONCLUSIONS: The Ross procedure provides good early results and an excellent long-term survival. It represents an excellent method of aortic valve replacement in children and young adults. Root reinforcement techniques and aortic reduction plasty may be beneficial, especially in adult patients with native aortic valve regurgitation.

Gastro-oesophageal reflux disease in type 2 diabetics: symptom load and pathophysiologic aspects - a retro-pro study.

BACKGROUND: Information about gastro-oesophageal reflux disease (GERD) in patients with Diabetes mellitus type 2 (T2D) is scarce, although the incidence of both disorders is increasing. METHODS: This "retro-pro" study compared 65 T2D patients to a control group of 130 age- and sex-matched non-diabetics. GERD was confirmed by gastroscopy, manometry, pH-metry and barium swallow. RESULTS: In patients with T2D compared to controls, dysphagia (32.3% vs. 13.1%; p = 0.001) and globus sensation (27.7% vs. 13.8%; p = 0.021) were found more frequently, whereas heartburn (76.9% vs. 88.5%; p = 0.046) and regurgitation (47.7% vs. 72.3%; p= 0.001) were predominant in non-diabetics. Despite higher body mass indices (31.1 ± 5.2 vs. 27.7 ± 3.7 kg/m²; p < 0.001), hiatal hernia was less frequent in T2D patients compared to controls (60.0% vs. 90.8%, p < 0.001). Lower oesophageal sphincter (LES) pressure was higher in patients with T2D (median 10.0 vs. 7.2 mmHg, p = 0.016). DeMeester scores did not differ between the groups. Helicobacter pylori infections were more common in T2D patients (26.2% vs. 7.7%, p = 0.001). Barrett metaplasia (21.5% vs. 17.7%), as well as low- (10.8% vs. 3.8%) and high-grade dysplasia (1.5% vs. 0%) were predominant in T2D patients. CONCLUSIONS: T2D patients exhibit different GERD symptoms, higher LES pressures and a decreased prevalence of hiatal hernia than non-diabetics, which may be related to worse oesophageal motility and, thus, a more functional rather than anatomical cause of GERD. Low-grade dysplasia was more than twice as high in T2D than in non-diabetics patients. TRIAL REGISTRATION: Ethics committee of the Medical University of Vienna, IRB number 720/2011.

Improvement of cardiac function in the failing rat heart after transfer of skeletal myoblasts engineered to overexpress placental growth factor.

BACKGROUND: Transplant of skeletal myoblasts is an attractive alternative to repair irreversibly damaged myocardium in ischemic heart failure. We investigated whether transplant of myoblasts overexpressing placental growth factor would stimulate angiogenesis and enhance myoblast survival in a rat heart failure model. METHODS: Three weeks after myocardial infarction, Sprague-Dawley rats in heart failure received intramyocardial injections of Ringer solution (control) or autologous myoblasts, unmodified or transfected with placental growth factor expression plasmid. Sham-operated animals served as noninfarct controls. Cardiac function was assessed by echocardiography to 86 days after engraftment. Immunocytochemistry and fluorescence imaging were used to investigate vessel formation, grafted myoblast survival, infarct wall thickness, and infarct size. Quantitative real-time reverse transcriptase polymerase chain reaction and Western blotting measured tissue messenger RNA and protein expressions. RESULTS: Left ventricular function significantly improved with time, and fractional shortening on day 86 was significantly enhanced in transfected myoblast group relative to control (P < .01) and unmodified myoblast (P < .05) groups. Vascular density (P < .01) and myoblast survival (P < .05) were enhanced in rats treated with transfected myoblasts relative to other groups (P < .05). Mean fraction of fibrotic scar tissue was decreased in unmodified and transfected myoblast groups relative to controls on day 86 (P < .05), and left ventricular wall thickness was significantly increased in transfected myoblast group relative to other groups (P < .05). CONCLUSIONS: Intramyocardial injections of autologous myoblasts overexpressing placental growth factor improved cardiac function, attenuated adverse cardiac remodeling, induced angiogenesis, and probably enhanced survival of grafted myoblasts.

Virus load dynamics of individual CMV-genotypes in lung transplant recipients with mixed-genotype infections.

Human cytomegalovirus (CMV) is a major cause of disease and transplant dysfunction in lung transplant recipients. Simultaneous emergence of more than one CMV-genotype can occur, and appears to be disadvantageous for the patient. In this study, the dynamics of individual CMV-genotypes in blood and lung was assessed within mixed CMV-genotype populations emerging after lung transplantation. In 69 plasma and 76 bronchoalveolar lavage samples of 16 lung transplant recipients with mixed CMV-genotype infections within the first year posttransplantation each of the major glycoprotein B (gB) and glycoprotein H (gH) genotypes was selectively quantified by genotype-specific quantitative TaqMan assays. The data obtained revealed that individually different genotype dynamics occurred for the individual patients and that the relative levels of the genotypes to each other may change over time. The quantitative development was independent of the specific gB-gH-genotype. In 10 of the 16 lung recipients the patient's individual genotype composition was the same in blood and lung. Genotype development during the follow-up was influenced by antiviral treatment. These data show for the first time that the CMV load used as diagnostic tool after transplantation is not always a constant entity but reflects the sum of the individual CMV-genotype dynamics developing over time.

Experimental stent-graft treatment of ascending aortic dissection.

BACKGROUND: This study assessed the feasibility of stent graft treatment of ascending aortic dissections in a porcine in vitro model. METHODS: The entire thoracic aortic aorta including the supraaortic branches was harvested from 12 adult pigs and an intimal tear was artificially created. The aortic annulus was then sewn into a silicon ring of a driving chamber. The distal aorta was connected to tubing with adjustable resistance elements. The circulation was driven by a hydraulic motor piston pump to mimic aortic flow and pressure. After creating a dissection by elevating the systolic aortic pressure to 180 mm Hg, a 2- x 2.6-cm covered stent graft was inserted through the brachiocephalic trunk using a specially designed delivery system. Stent graft placement was performed under continuous ultrasound control. RESULTS: The longitudinal length of the created ascending aortic dissection was 1.8 +/- 0.39 cm. Ultrasound studies revealed successful deployment of the stent graft and closure of the false lumen in all 12 cases. Diameter and area of the true lumen increased from 0.52 +/- 0.15 cm to 2.54 +/- 0.36 cm (p < 0.05) and from 0.78 +/- 0.27 cm2 to 5.13 +/- 1.35 cm2 (p < 0.05), respectively. The circumference of the true lumen increased from 4.50 +/- 0.52 cm to 7.96 +/- 1.2 cm (p < 0.05). Ultrasound studies also revealed uncompromised function of the aortic valve in all cases. No dislodging of stent grafts was observed. CONCLUSIONS: Given ideal anatomy, experimental stent graft placement for ascending aortic dissection is feasible and achieves complete closure of the false lumen.

Biomechanical properties of decellularized porcine pulmonary valve conduits.

Tissue-engineered heart valves constructed from a xenogeneic or allogeneic decellularized matrix might overcome the disadvantages of current heart valve substitutes. One major necessity besides effective decellularization is to preserve the biomechanical properties of the valve. Native and decellularized porcine pulmonary heart valve conduits (PPVCs) (with [n = 10] or without [n = 10] cryopreservation) were compared to cryopreserved human pulmonary valve conduits (n = 7). Samples of the conduit were measured for wall thickness and underwent tensile tests. Elongation measurement was performed with a video extensometer. Decellularized PPVC showed a higher failure force both in longitudinal (+73%; P < 0.01) and transverse (+66%; P < 0.001) direction compared to human homografts. Failure force of the tissue after cryopreservation was still higher in the porcine group (longitudinal: +106%, P < 0.01; transverse: +58%, P < 0.001). In comparison to human homografts, both decellularized and decellularized cryopreserved porcine conduits showed a higher extensibility in longitudinal (decellularized: +61%, P < 0.001; decellularized + cryopreserved: +51%, P < 0.01) and transverse (decellularized: +126%, P < 0.001; decellularized + cryopreserved: +118%, P < 0.001) direction. Again, cryopreservation did not influence the biomechanical properties of the decellularized porcine matrix.

Permanent chronic atrial fibrillation: is pulmonary vein isolation alone enough?

BACKGROUND: The efficacy of mere pulmonary vein isolation epicardially for the treatment of permanent chronic atrial fibrillation, in comparison with the left atrial endocardial maze procedure was evaluated. METHODS: Retrospective data collection and analysis toward the outcome of 72 consecutive patients who underwent left atrial maze procedures between January 2003 and December 2005 was performed. Surgical ablation was performed concomitantly with valve and (or) coronary procedures. Group I (n = 29) received an endocardial left atrial ablation using unipolar saline irrigated radiofrequency (Medtronic Cardioblate surgical ablation pen; Medtronic Inc, Minneapolis, MN). Group II (n = 43) received epicardial isolation of the pulmonary veins using bipolar saline irrigated radiofrequency (Medtronic Cardioblate). Follow-up included 24h electrocardiogram and echocardiography 6 and 12 months postoperatively. RESULTS: Mean follow-up was 19.5 +/- 1.0 months (17.7 +/- 19.5 months group I vs 20.6 +/- 1.1 months group II). Both groups were comparable with regard to duration of preoperative atrial fibrillation, European system for cardiac operative risk evaluation, left ventricular ejection fraction, aortic cross-clamp time, bypass time, intensive care unit and hospital stay (p > 0.05). No maze procedure-related mortality was observed. In group I, three patients required postoperative pacemaker implantation due to atrioventricular (AV) bloc, bradycardia, and sick sinus syndrome, respectively. In group II, five patients required postoperative pacemaker implantation (three AV bloc and two bradycardia). Freedom from atrial fibrillation at last follow-up was 85.7% and 58.5% in groups I and II, respectively (p = 0.016). CONCLUSIONS: Pulmonary vein isolation alone seems to be insufficient in treating permanent chronic atrial fibrillation. In case of chronic permanent atrial fibrillation, left atrial endocardial maze, providing the connection lines to the mitral annulus and (or) between the pulmonary veins, seems to be mandatory.

Matrix metalloproteases and their tissue inhibitor in cardiac transplantation.

OBJECTIVE: Multiple studies have shown that matrix metalloproteases (MMPs) are involved in the pathologic reactions occurring as a consequence of cardiac transplantation, including ischemia-reperfusion injury and allograft rejection. This study sought to determine the temporal profile of MMP serum levels following cardiac transplantation. METHODS: Endomyocardial biopsies and serum samples were obtained from 66 recipients at 1, 2, 3, 4, 7, 12, 24, and 52 weeks post-transplant during the routine follow-up protocol, and MMP-1, MMP-8, MMP-9, and tissue inhibitor of metalloproteases (TIMP)-1 serum concentrations were measured by enzyme-linked immunosorbent assay (ELISA). Immunosuppression comprised cyclosporine A (CyA; n=46) or tacrolimus (TAC; n=20) with mycophenolate mofetil and steroids. RESULTS: Increased MMP-8, MMP-9, and TIMP-1 serum levels were observed during the first 2 weeks following transplantation compared to the later time points. MMP-1 was increased at 2 and 3 weeks post-transplant compared to all later time points. No correlation of MMP or TIMP serum concentrations with infection episodes was observed. CONCLUSIONS: Early increase in MMP and TIMP serum levels following cardiac transplantation indicates involvement of these molecules in the reaction of the transplant to ischemia-reperfusion or early immunologic adaptation processes of the host. Further investigation of the relationship between MMP and TIMP serum levels and clinical conditions following transplantation including allograft rejection and hemodynamic graft function is necessary.

Cystic formation of the foramen ovale mimicking a right atrial myxoma.

A 65-year-old woman presented with shortness of breath, stenocardia, and tachycardia. She underwent several steps of examination. Echocardiography showed a suspicious formation in the right atrium extending into the inferior caval vein. The lesion was suspicious for a myxoma, a thrombus, or a malformation. Intraoperatively this formation presented as a cystic formation connected to the right atrial wall in the area of the foramen secundum and filled with blood and five calcified thrombi. We hypothesize that a slit-like opening in the foramen ovale produced a valve-like mechanism bulging parts of the septum secundum and produced this cystic formation.

Decellularization does not eliminate thrombogenicity and inflammatory stimulation in tissue-engineered porcine heart valves.

BACKGROUND AND AIM OF THE STUDY: In tissue engineering of heart valves using decellularized xenogenic valves, it has been suggested that cell elimination would result in a biologically inert matrix. The aim of this in-vitro investigation was to evaluate different decellularization methods in regard to the completeness of cell removal, inflammatory response, and thrombocyte activation. METHODS: Decellularized porcine Synergraft valves were compared with porcine pulmonary conduits decellularized with Triton X-100, sodium deoxycholate, Igepal CA-630 and ribonuclease. Completeness of decellularization was evaluated with staining for nuclei and alpha-Gal epitope. Decellularized heart valves with and without seeding with endothelial cells (ECs) were incubated with human platelet-rich plasma and stained for CD41 and PAC-1 to evaluate thrombocyte activation. Samples were processed for laser scanning microscopy (LSM) and scanning electron microscopy (SEM). Migration of human monocytic cells towards extracted valve proteins was tested. RESULTS: In contrast to the Synergraft, complete cell removal and elimination of the alpha-gal epitope was achieved with the new decellularization method. Numerous adherent and activated platelets were found on the decellularized matrix. This was inhibited by seeding with ECs. Even in completely cell-free valve tissue extracellular matrix proteins attracted human monocytic cells as in early inflammation, depending on whether porcine or human tissue was used. CONCLUSION: Important differences were found in the decellularization efficacy of treatment methods. However, even complete elimination of cells and their remnants did not result in a biologically inert matrix. The decellularized porcine heart valve matrix has the potential to attract inflammatory cells and to induce platelet activation. These findings suggest that it will be important to control the different inflammation-stimulating factors if porcine tissues are to be used successfully in tissue engineering.

The decellularized porcine heart valve matrix in tissue engineering: platelet adhesion and activation.

An approach in tissue engineering of heart valves is the use of decellularized xenogeneic matrices to avoid immune response after implantation. The decellularization process must preserve the structural components of the extracellular matrix to provide a biomechanically stable scaffold. However, it is known that in vascular lesions platelet adhesion to extracellular matrix components occurs and platelet activation is induced. In the present study we examined the effects of a decellularized porcine heart valve matrix on thrombocyte activation and the influence of re-endothelialisation in vitro. Porcine pulmonary conduits were decellularized using Triton X-100, Na-deoxycholate and Igepal CA-630 followed by a ribonuclease digestion. Cryostat sections of decellularized heart valves with and without seeding with human umbilical vein endothelial cells (HUVEC) were incubated with platelet rich plasma. Samples were either stained with fluorescent antibodies for CD41 and PAC-I (recognizing the activated fibrinogen receptor) or fixed with glutaraldehyde. Thereafter, the samples were processed for laser scanning microscopy (LSM) or scanning electron microscopy (SEM). Examination by LSM showed numerous platelets with co-localized staining for CD41 and PAC-1 on the nonseeded decellularized heart valve matrix whereas after seeding with endothelial cells no platelet activation was detected. SEM revealed platelet adhesion and aggregate formation only on the surface of the non-seeded or partially denuded matrix specimens. We show in this study that the decellularized porcine matrix acts as a platelet-activating surface. Seeding with endothelial cells effectively abolishes the platelet adhesion and activation and therefore is necessary to eliminate thrombogenicity in tissue engineered heart valves.

Presence and elimination of the xenoantigen gal (alpha1, 3) gal in tissue-engineered heart valves.

Tissue engineering of heart valves promises to create functional autologous tissue with the potential for regeneration and growth without the limitations of current heart valve prostheses. The appropriate valve matrix is essential. Porcine heart valves are attractive because of their anatomical similarity. Decellularization is used for antigen reduction. The efficacy of published protocols varies, however. The absence of a specific immunological or unspecific inflammatory reaction is mandatory. The porcine cell-specific alpha-Gal epitope is known to be responsible for hyperacute rejection in xenotransplantation. In tissue engineering residual alpha-Gal epitope may induce severe inflammation in humans and may lead to graft failure. In this study porcine pulmonary conduits were decellularized with Triton X-100, sodium deoxycholate, Igepal CA-630, and ribonuclease treatment and were compared with specimens of the commercially available porcine decellularized SynerGraft regarding cell removal and elimination of the alpha-Gal epitope. In addition, samples of a porcine bioprosthesis were examined for the presence of the alpha-Gal epitope. In conclusion, we describe for the first time the presence of the alpha-Gal epitope in clinically used porcine bioprostheses and the first generation of a commercial tissue-engineered heart valve. In contrast, complete cell and alpha-Gal removal was achieved by a decellularization procedure developed by our group.

Tissue engineering of heart valves: decellularized porcine and human valve scaffolds differ importantly in residual potential to attract monocytic cells.

BACKGROUND: Tissue-engineered or decellularized heart valves have already been implanted in humans or are currently approaching the clinical setting. The aim of this study was to examine the migratory response of human monocytic cells toward decellularized porcine and human heart valves, a pivotal step in the early immunologic reaction. METHODS AND RESULTS: Porcine and human pulmonary valve conduits were decellularized, and migration of U-937 monocytic cells toward extracted heart valve proteins was examined in a transmigration chamber in vitro. Homogenized tissue specimens were size fractionated by SDS-PAGE. The decellularization procedure effectively reduced the migration of human monocytes toward all heart valve tissue. However, only the antigen reduction of human pulmonary valves abolished the monocytic response (wall, 0.88+/-0.19% versus 30.20+/-3.93% migrated cells [mean+/-SEM]; cusps, 0.10+/-0.06% versus 10.24+/-1.83%) and was significantly lower (P<0.05) than that of the decellularized porcine equivalent (wall, 5.03+/-0.14% versus 24.31+/-2.38%; cusps, 3.18+/-0.38% versus 10.24+/-1.83%). SDS-PAGE of the pulmonary heart valve tissue revealed that considerable amounts of proteins with different molecular weights that were not detected in the human equivalent remain in the decellularized porcine heart valve. CONCLUSIONS: We describe for the first time that the remaining potential of decellularized pulmonary heart valves to attract monocytic cells depends strongly on whether porcine or human scaffolds were used. These findings will have an important impact on further investigations in the field of heart valve tissue engineering.

Extended donor criteria for lung transplantation--a clinical reality.

OBJECTIVE: Standard lung donor criteria have been established on opinions and individual experiences rather than on existing evidence. Since the scarcity of donor organs is one of the major limitations to lung transplantation, extension of donor lung criteria might considerably increase the donor pool. This study therefore evaluates the outcome, achieved with the use of extended donors versus standard donors and aims to redefine lung donor criteria. METHODS: We performed a retrospective analysis of 98 consecutive primary lung transplantations from 94 donors from 1/2001 to 12/2002. Donors were classified as extended if they fulfilled at least one criteria: age >55 years, PaO(2) at FiO(2)/PEEP 5 <300mmHg, tobacco history >20 pack years, inhalative drug abuse, presence of infiltration on chest X-ray or purulent secretions at bronchoscopy. Recipients were stratified in two groups according to whether they received a 'standard' or 'extended' organ. Postoperative complications, extubation time, ICU and hospital stay and survival were compared. RESULTS: Twenty-three (24.5%) donors were extended. Twenty-six recipients (26.55%) received organs from extended donors. Differences in intubation times (12+/-2 days standard vs. 14+/-5 days extended, P=0.70), ICU stay (16+/-2 days standard vs. 18+/-5 days extended, P=0.74) and hospital stay (38+/-4 days standard vs. 40+/-6 days extended, P=0.71) were not statistically significant. Postoperative bleeding rates were comparable (n=14 standard vs. n=3 extended) as well as bronchial anastomotic complications (n=7 standard vs. n=3 extended). Three months survival was 88.89% in the standard group vs. 92.31% in the extended group. One year survival is comparable as well with 81.94 vs. 84.62%, respectively. CONCLUSIONS: The use of lung donors who fail to meet standard criteria does not impair short and medium term results compared to standard lung donors. The impact on long term development of BOS has yet to be evaluated. The strict application of standard lung donor criteria excludes a considerable number of lungs potentially suitable for transplantation, thus liberalisation of donor criteria might help to overcome donor shortage.