Circulating FGF18 is decreased in pleural mesothelioma but not correlated with disease prognosis.

BACKGROUND: Pleural mesothelioma (PM) is a relatively rare malignancy with limited treatment options and dismal prognosis. We have previously found elevated FGF18 expression in PM tissue specimens compared with normal mesothelium. The objective of the current study was to further explore the role of FGF18 in PM and evaluate its suitability as a circulating biomarker. METHODS: FGF18 mRNA expression was analyzed by real-time PCR in cell lines and in silico in datasets from the Cancer Genome Atlas (TCGA). Cell lines overexpressing FGF18 were generated by retroviral transduction and cell behavior was investigated by clonogenic growth and transwell assays. Plasma was collected from 40 PM patients, six patients with pleural fibrosis, and 40 healthy controls. Circulating FGF18 was measured by ELISA and correlated to clinicopathological parameters. RESULTS: FGF18 showed high mRNA expression in PM and PM-derived cell lines. PM patients with high FGF18 mRNA expression showed a trend toward longer overall survival (OS) in the TCGA dataset. In PM cells with low endogenous FGF18 expression, forced overexpression of FGF18 resulted in reduced growth but increased migration. Surprisingly, despite the high FGF18 mRNA levels observed in PM, circulating FGF18 protein was significantly lower in PM patients and patients with pleural fibrosis than in healthy controls. No significant association of circulating FGF18 with OS or other disease parameters of PM patients was observed. CONCLUSIONS: FGF18 is not a prognostic biomarker in PM. Its role in PM tumor biology and the clinical significance of decreased plasma FGF18 in PM patients warrant further investigation.

Neoadjuvant immune-checkpoint inhibitors in lung cancer - a primer for radiologists.

The introduction of neoadjuvant immune checkpoint inhibitors plus platinum-based chemotherapy has changed treatment regimens of patient's early-stage lung cancer. This treatment combination induces high rates of complete pathologic response and improves clinical endpoints. Imaging plays a fundamental role in assessment of treatment response, monitoring of (immune-related) adverse events and enables both the surgeon and pathologist optimal treatment and diagnostic workup of the resected tumor samples. Knowledge of the strengths and weaknesses of diagnostic imaging in this setting are essential for radiologists to provide valuable input in multidisciplinary team decisions.

Mesothelioma-associated fibroblasts enhance proliferation and migration of pleural mesothelioma cells via c-Met/PI3K and WNT signaling but do not protect against cisplatin.

BACKGROUND: Pleural mesothelioma (PM) is an aggressive malignancy with poor prognosis. Unlike many other cancers, PM is mostly characterized by inactivation of tumor suppressor genes. Its highly malignant nature in absence of tumor driving oncogene mutations indicates an extrinsic supply of stimulating signals by cells of the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are an abundant cell type of the TME and have been shown to drive the progression of several malignancies. The aim of the current study was to isolate and characterize patient-derived mesothelioma-associated fibroblasts (Meso-CAFs), and evaluate their impact on PM cells. METHODS: Meso-CAFs were isolated from surgical specimens of PM patients and analyzed by array comparative genomic hybridization, next generation sequencing, transcriptomics and proteomics. Human PM cell lines were retrovirally transduced with GFP. The impact of Meso-CAFs on tumor cell growth, migration, as well as the response to small molecule inhibitors, cisplatin and pemetrexed treatment was investigated in 2D and 3D co-culture models by videomicroscopy and automated image analysis. RESULTS: Meso-CAFs show a normal diploid genotype without gene copy number aberrations typical for PM cells. They express CAF markers and lack PM marker expression. Their proteome and secretome profiles clearly differ from normal lung fibroblasts with particularly strong differences in actively secreted proteins. The presence of Meso-CAFs in co-culture resulted in significantly increased proliferation and migration of PM cells. A similar effect on PM cell growth and migration was induced by Meso-CAF-conditioned medium. Inhibition of c-Met with crizotinib, PI3K with LY-2940002 or WNT signaling with WNT-C59 significantly impaired the Meso-CAF-mediated growth stimulation of PM cells in co-culture at concentrations not affecting the PM cells alone. Meso-CAFs did not provide protection of PM cells against cisplatin but showed significant protection against the EGFR inhibitor erlotinib. CONCLUSIONS: Our study provides the first characterization of human patient-derived Meso-CAFs and demonstrates a strong impact of Meso-CAFs on PM cell growth and migration, two key characteristics of PM aggressiveness, indicating a major role of Meso-CAFs in driving PM progression. Moreover, we identify signaling pathways required for Meso-CAF-mediated growth stimulation. These data could be relevant for novel therapeutic strategies against PM.

Impact of fibrinogen levels and modified Glasgow prognostic score on survival of stage III/N2 non-small cell lung cancer patients treated with neoadjuvant therapy and radical resection.

PURPOSE: The prognostic value of pretreatment and preoperative fibrinogen plasma levels and the modified Glasgow prognostic score (mGPS) in stage III/N2 non-small cell lung cancer (NSCLC) patients who receive neoadjuvant treatment followed by radical surgery is yet unclear. METHODS: Fibrinogen levels and mGPS of 84 patients with initial stage III/N2 NSCLC, who received neoadjuvant therapy followed by complete surgical resection from 2002 to 2014 were retrospectively analyzed and correlated with clinical parameters and overall survival (OS). Data were analyzed using log-rank and Cox regression analysis adjusted for clinical and pathological factors. RESULTS: Median serum fibrinogen level after neoadjuvant treatment was 439 mg/dL (IQR 158 mg/dL). Elevated fibrinogen levels (> 400 mg/dL) after neoadjuvant treatment were significantly associated with poorer OS (28.2 months vs. 60.9 months, HR 0.562, p = 0.048). Importantly, a decrease in fibrinogen levels after neoadjuvant treatment (n = 34) was found to be an independent predictor for favorable OS in multivariate analysis (HR 0.994, p = 0.025). Out of 80 patients, 55, 19 and 6 patients had a mGPS of 0, 1 and 2, respectively. Moreover, elevated mGPS after neoadjuvant treatment (mGPS 1-2) showed a non-significant trend for poorer OS compared to mGPS 0 (28.2 vs. 46.5 months, HR 0.587, p = 0.066). CONCLUSION: Elevated fibrinogen levels after neoadjuvant therapy prior to surgery in stage III/N2 NSCLC patients are associated with significant disadvantage for OS. A decrease in fibrinogen levels after neoadjuvant therapy was found to be a predictor for superior OS in this retrospective patient cohort.

Trabectedin Is Active against Two Novel, Patient-Derived Solitary Fibrous Pleural Tumor Cell Lines and Synergizes with Ponatinib.

Solitary fibrous tumor of the pleura (SFT) is a rare disease. Besides surgery combined with radiotherapy in nondisseminated stages, curative options are currently absent. Out of fourteen primo-cell cultures, established from surgical SFT specimens, two showed stable in vitro growth. Both cell models harbored the characteristic NAB2-STAT6 fusion and were further investigated by different preclinical methods assessing cell viability, clone formation, and protein regulation upon single-drug treatment or in response to selected treatment combinations. Both fusion-positive cell models showed-in line with the clinical experience and the literature-a low to moderate response to most of the tested cytotoxic and targeted agents. However, the multi-tyrosine kinase inhibitors ponatinib and dasatinib, as well as the anti-sarcoma compound trabectedin, revealed promising activity against SFT growth. Furthermore, both cell models spontaneously presented strong FGFR downstream signaling targetable by ponatinib. Most interestingly, the combination of either ponatinib or dasatinib with trabectedin showed synergistic effects. In conclusion, this study identified novel trabectedin-based treatment combinations with clinically approved tyrosine kinase inhibitors, using two newly established NAB2-STAT6 fusion-positive cell models. These findings can be the basis for anti-SFT drug repurposing approaches in this rare and therapy-refractory disease.

Oblique Carinal End-to-end Anastomosis for Pig Bronchus in Organ Donor and Lung Transplant Recipient.

Pig bronchi are rare anomalies in which the right upper lobe bronchus originates above the carina. During surgery this can lead to technical challenges associated with the bronchial anastomosis, especially during lung transplantation. We herein report the case of a combined liver-lung transplantation with a pig bronchus in both the organ donor and transplant recipient. In both cases the bronchi originated slightly above the level of the carina facilitating an oblique resection and a single tracheobronchial anastomosis with a running suture. Follow-up bronchoscopy showed a completely healed anastomosis with no evidence of malacia or stenosis.

Prognostic impact of PD-1 and PD-L1 expression in malignant pleural mesothelioma: an international multicenter study.

BACKGROUND: Programmed cell death 1/programmed death ligand 1 (PD-1/PD-L1) immune-checkpoint blockade is a promising new therapeutic strategy in cancer. However, expression patterns and prognostic significance of PD-L1 and PD-1 are still controversial in human malignant pleural mesothelioma (MPM). METHODS: Formalin-fixed paraffin-embedded (FFPE) tumor samples from 203 MPM patients receiving standard treatment without immunotherapy were collected from 5 European centers. PD-L1 and PD-1 expression of tumor cells (TCs) and tumor-infiltrating lymphocytes (TILs) were measured by immunohistochemistry and correlated with clinical parameters and long-term outcome. RESULTS: High (>10%) PD-L1 TC and PD-1 TILs expressions were found in 18 (8%) and 39 (24%) patients, respectively. PD-L1 was rarely expressed by TILs [≥1%, n=13 (8%); >10%, n=1]. No significant associations were found between the PD-L1 or PD-1 expression of TCs or TILs and clinicopathological parameters such as stage or histological subtype. Notably, patients with high (>10%) TC-specific PD-L1 expression exhibited significantly worse median overall survival (OS) (6.3 vs. 15.1 months of those with low TC PD-L1 expression; HR: 2.51, P<0.001). In multivariate cox regression analysis adjusted for clinical parameters, high TC PD-L1 expression (>10%) proved to be an independent negative prognostic factor for OS (HR: 2.486, P=0.005). There was no significant correlation between PD-L1 or PD-1 expression of TILs and OS. CONCLUSIONS: In this multicenter cohort study, we demonstrate that high (>10%) PD-L1 expression of TCs independently predicts worse OS in MPM. Further studies are warranted to investigate the value of PD-L1/PD-1 expression as a marker for treatment response in MPM patients receiving immunotherapy.

Outcome of lung transplantation in cystic fibrosis patients with severe asymmetric chest cavities.

Objective: A small but relevant proportion of patients with cystic fibrosis develop severely asymmetric chest cavities during the course of their disease. For these patients, the best surgical approach for lung transplantation (LTx) and optimal size matching strategies are controversial. Methods: All cystic fibrosis patients with asymmetric chest cavities who underwent LTx at the Medical University of Vienna between 2003 and 2017 were identified (n = 13). Patients were grouped according to different surgical strategies: unilateral full-size and contralateral lobar transplantation (n = 4), standard double LTx after mobilization/repositioning of the mediastinum (n = 3), oversized single LTx followed by pneumonectomy on the smaller contralateral side (n = 4), and single LTx after a remote contralateral pneumonectomy (n = 2). Results: Compared with cystic fibrosis patients with symmetric chests (n = 276, control group), the perioperative management of patients with asymmetric chests was often more complicated. Consequently, 90-day mortality was heightened (23.1% vs 6.5%). Despite this, long-term survival was good with a 5-year survival rate of 69% compared with 78%. Of note, outcome seemed superior for patients who surgery was undertaken with a bilateral compared with a unilateral approach. Conclusions: Severely asymmetric chest cavities present challenges in regard to the surgical strategy, size matching, and postoperative management. However, in carefully selected patients, LTx provides an adequate long-term outcome.

Long-term Survival After Salvage Surgery for a Giant Primary Rib Osteosarcoma.

A 29-year-old woman with a primary rib osteosarcoma declined treatment and was readmitted 20 months later in life-threatening condition caused by major local tumor progression with severe mediastinal shifting, and without distant metastases. She underwent extended tumor resection with palliative intent and recovered well after a prolonged course with post-pneumonectomy empyema. Further treatment was declined, and she presented again 4.5 years later with local chest wall recurrence that was completely resected. Currently, 7 years after diagnosis, the patient is free from disease. In this rare case, salvage surgery was associated with an unexpected favorable long-term outcome.

Donor ventilation parameters as predictors for length of mechanical ventilation after lung transplantation: Results of a prospective multicenter study.

BACKGROUND: The evaluation of donor lungs heavily depends on the subjective judgment of the retrieval surgeon. As a consequence, acceptance rates vary significantly among transplant centers. We aimed to determine donor ventilation parameters in a prospective study and test if they could be used as objective quality criteria during organ retrieval. METHODS: A prospective evaluation of lung donors was performed in 3 transplant centers. Ventilation parameters were collected at the time of retrieval using a standardized ventilation protocol. Recipient length of mechanical ventilation (LMV) was defined as the primary end point, and collected data was used to build linear models predicting LMV. RESULTS: In total, 166 donors were included in this study. Median LMV after transplantation was 32 hours (interquartile range: 20-63 hours). Peak inspiratory pressure and dynamic compliance (Cdyn) at the time of retrieval, but not the partial pressure of oxygen/fraction of inspired oxygen (P/F) ratio, correlated with recipient LMV in Spearman correlations (r = 0.280, p = 0.002; r = -0.245, p = 0.003; and r = 0.064, p = 0.432, respectively). Linear models were built to further evaluate the impact of donor ventilation parameters on LMV. The first model was based on donor P/F ratio, donor age, donor intubation time, donor smoking history, donor partial pressure of carbon dioxide, aspiration, chest trauma, and pathologic chest X-ray. This model performed poorly (multiple R-squared = 0.063). In a second model, donor ventilation parameters were included, and Cdyn was identified as the strongest predictor for LMV. The third model was extended by recipient factors, which significantly improved the robustness of the model (multiple R-squared = 0.293). CONCLUSION: In this prospective evaluation of donor lung parameters, currently used donor quality criteria poorly predicted recipient LMV. Our data suggest that Cdyn is a strong donor-bound parameter to predict short-term graft performance; however, recipient factors are similarly relevant.

Ventilation parameters and early graft function in double lung transplantation.

BACKGROUND: Currently, the primary graft dysfunction (PGD) score is used to measure allograft function in the early post-lung transplant period. Although PGD grades at later time points (T48 hours and T72 hours) are useful to predict mid- and long-term outcomes, their predictive value is less relevant within the first 24 hours after transplantation. This study aimed to evaluate the capability of PGD grades to predict prolonged mechanical ventilation (MV) and compare it with a model derived from ventilation parameters measured on arrival at the intensive care unit (ICU). METHODS: A retrospective single-center analysis of 422 double lung transplantations (LTxs) was performed. PGD was assessed 2 hours after arrival at ICU, and grades were associated with length of MV (LMV). In addition, peak inspiratory pressure (PIP), ratio of the arterial partial pressure of oxygen to fraction of inspired oxygen (P/F ratio), and dynamic compliance (cDyn) were collected, and a logistic regression model was created. The predictive capability for prolonged MV was calculated for both (the PGD score and the model). In a second step, the created model was externally validated using a prospective, international multicenter cohort including 102 patients from the lung transplant centers of Vienna, Toronto, and Budapest. RESULTS: In the retrospective cohort, a high percentage of extubated patients was reported at 24 hours (35.1%), 48 hours (68.0%), and 72 hours (80.3%) after transplantation. At T0 (time point defined as 2 hours after arrival at the ICU), patients with PGD grade 0 had a shorter LMV with a median of 26 hours (interquartile range [IQR]: 16-47 hours) than those with PGD grade 1 (median: 42 hours, IQR: 27-50 hours), PGD grade 2 (median: 37.5 hours, IQR: 15.5-78.5 hours), and PGD grade 3 (median: 46 hours, IQR: 27-86 hours). However, IQRs largely overlapped for all grades, and the value of PGD to predict prolonged MV was poor. A total of 3 ventilation parameters (PIP, cDyn, and P/F ratio), determined at T0, were chosen on the basis of clinical reasoning. A logistic regression model including these parameters predicted prolonged MV (>72 hours) with an optimism-corrected area under the curve (AUC) of 0.727. In the prospective validation cohort, the model proved to be stable and achieved an AUC of 0.679. CONCLUSIONS: The prediction model reported in this study combines 3 easily obtainable variables. It can be employed immediately after LTx to quantify the risk of prolonged MV, an important early outcome parameter.

Malignant pleural mesothelioma: recent developments.

PURPOSE OF REVIEW: Malignant pleural mesothelioma (MPM) is a rare, but aggressive tumor with still poor prognosis. In this article, we focus on recent developments in the management of MPM including diagnosis, staging, biomarkers, and treatment strategies. RECENT FINDINGS: Molecular markers such as programmed death-ligand 1 (PDL-1), Breast Cancer gene 1-associated protein gene, and cyclin-dependent kinase inhibitor 2A (CDKN2A) have prognostic impact and should be considered for assessment in patient samples. In addition to histological subtype and tumor pattern, tumor volumetry plays an increasing important role in staging, assessment of treatment response, and prediction of survival. Several new blood-based biomarkers have been recently reported including peripheral blood DNA methylation, microRNAs, fibulin, and high-mobility group box 1, but have not been established in clinical routine use yet. Regarding treatment, targeted therapies, immunotherapy, and vaccination are considered as new promising strategies. Moreover, extended pleurectomy/decortication is favored over extrapleural pneumonectomy (EPP) and intensity-modulated radiotherapy represents a possible approach in combination with EPP and pleurectomy/decortication. Intracavitary treatment options are promising and deserve further investigations. SUMMARY: Overall, there has not been a real breakthrough in the treatment of MPM. Further research and clinical trials are needed to evaluate outcome and to identify new potential treatment candidates.

Prostaglandin D2 strengthens human endothelial barrier by activation of E-type receptor 4.

Life-threatening inflammatory conditions such as acute respiratory distress syndrome or sepsis often go hand in hand with severe vascular leakage. During inflammation, endothelial cell integrity and intact barrier function are crucial to limit leukocyte and plasma extravasation. Prostaglandin D2 (PGD2) is a potent inflammatory lipid mediator with vasoactive properties. Previous studies suggest that PGD2 is involved in the regulation of endothelial barrier function; however, it is unclear whether this is also true for primary human pulmonary microvascular endothelial cells. Furthermore, as PGD2 is a highly promiscuous ligand, we set out to determine which receptors are important in human pulmonary endothelial cells. In the current study, we found that PGD2 and the DP1 agonist BW245c potently strengthened pulmonary and dermal microvascular endothelial cell barrier function and protected against thrombin-induced barrier disruption. Yet surprisingly, these effects were mediated only to a negligible extent via DP1 receptor activation. In contrast, we observed that the EP4 receptor was most important and mediated the barrier enhancement by PGD2 and BW245c. Stimulation with PGE2 or PGD2 reduced AKT phosphorylation which could be reversed by prior blockade of EP4 receptors. These data demonstrate a novel mechanism by which PGD2 may modulate inflammation and emphasizes the role of EP4 receptors in human endothelial cell function.

TWIST1 Drives Smooth Muscle Cell Proliferation in Pulmonary Hypertension via Loss of GATA-6 and BMPR2.

Rationale: The bHLH (basic helix-loop-helix) transcription factor TWIST1 (Twist-related protein 1) controls cell proliferation and differentiation in tissue development and disease processes. Recently, endothelial TWIST1 has been linked to pulmonary hypertension (PH) and endothelial-to-mesenchymal transition, yet the role of TWIST1 in smooth muscle cells (SMCs) remains so far unclear.Objectives: To define the role of TWIST1 in SMCs in the pathogenesis of PH.Methods: SMC-specific TWIST1-deficient mice, SMC-specific TWIST1 silencing in rats, mass spectrometry, immunoprecipitation, and chromatin immunoprecipitation were used to delineate the role of SMC TWIST1 in PH.Measurements and Main Results: In pulmonary vessels from patients with PH and rodent PH models, TWIST1 expression was markedly increased and predominantly localized to SMCs. SMC-specific TWIST1 deficiency or silencing attenuated the development of PH and distal vessel muscularization in chronically hypoxic mice and in monocrotaline-treated rats. In vitro, TWIST1 inhibition or silencing prevented pulmonary artery SMC proliferation and migration. Mechanistically, the observed effects were mediated, at least in part, by TWIST1-dependent degradation of GATA-6 (GATA-binding protein 6). BMPR2 (bone morphogenetic protein receptor-2) was identified as a novel downstream target of GATA-6, which directly binds to its promoter. Inhibition of TWIST1 promoted the recruitment of GATA-6 to the BMPR2 promoter and restored BMPR2 functional expression.Conclusions: Our findings identify a key role for SMC TWIST1 in the pathogenesis of lung vascular remodeling and in PH that is partially mediated via reduced GATA-6-dependent BMPR2 expression. Inhibition of SMC TWIST1 may constitute a new therapeutic strategy for the treatment of PH.

Basement Membrane Remodeling Controls Endothelial Function in Idiopathic Pulmonary Arterial Hypertension.

The extracellular matrix (ECM) increasingly emerges as an active driver in several diseases, including idiopathic pulmonary arterial hypertension (IPAH). The basement membrane (BM) is a specialized class of ECM proteins. In pulmonary arteries, the BM is in close contact and direct proximity to vascular cells, including endothelial cells. So far, the role of the BM has remained underinvestigated in IPAH. Here, we aimed to shed light on the involvement of the BM in IPAH, by addressing its structure, composition, and function. On an ultrastructural level, we observed a marked increase in BM thickness in IPAH pulmonary vessels. BM composition was distinct in small and large vessels and altered in IPAH. Proteoglycans were mostly responsible for distinction between smaller and larger vessels, whereas BM collagens and laminins were more abundantly expressed in IPAH. Type IV collagen and laminin both strengthened endothelial barrier integrity. However, only type IV collagen concentration dependently increased cell adhesion of both donor and IPAH-derived pulmonary arterial endothelial cells (PAECs) and induced nuclear translocation of mechanosensitive transcriptional coactivator of the hippo pathway YAP (Yes-activated protein). On the other hand, laminin caused cytoplasmic retention of YAP in IPAH PAECs. Accordingly, silencing of COL4A5 and LAMC1, respectively, differentially affected tight junction formation and barrier integrity in both donor and IPAH PAECs. Collectively, our results highlight the importance of a well-maintained BM homeostasis. By linking changes in BM structure and composition to altered endothelial cell function, we here suggest an active involvement of the BM in IPAH pathogenesis.

The Determination of Immunomodulation and Its Impact on Survival of Rectal Cancer Patients Depends on the Area Comprising a Tissue Microarray.

BACKGROUND: T cell density in colorectal cancer (CRC) has proven to be of high prognostic importance. Here, we evaluated the influence of a hyperfractionated preoperative short-term radiation protocol (25 Gy) on immune cell density in tumor samples of rectal cancer (RC) patients and on patient survival. In addition, we assessed spatial tumor heterogeneity by comparison of analogue T cell quantification on full tissue sections with digital T cell quantification on a virtually established tissue microarray (TMA). METHODS: A total of 75 RC patients (60 irradiated, 15 treatment-naïve) were defined for retrospective analysis. RC samples were processed for immunohistochemistry (CD3, CD8, PD-1, PD-L1). Analogue (score 0-3) as well as digital quantification (TMA: 2 cores vs. 6 cores, mean T cell count) of marker expression in 2 areas (central tumor, CT; invasive margin, IM) was performed. Survival was estimated on the basis of analogue as well as digital marker densities calculated from 2 cores (Immunoscore: CD3/CD8 ratio) and 6 cores per tumor area. RESULTS: Irradiated RC samples showed a significant decrease in CD3 and CD8 positive T cells, independent of quantification mode. T cell densities of 6 virtual cores approximated to T cell densities of full tissue sections, independent of individual core density or location. Survival analysis based on full tissue section quantification demonstrated that CD3 and CD8 positive T cells as well as PD-1 positive tumor infiltrating leucocytes (TILs) in the CT and the IM had a significant impact on disease-free survival (DFS) as well as overall survival (OS). In addition, CD3 and CD8 positive T cells as well as PD-1 positive TILs in the IM proved as independent prognostic factors for DFS and OS; in the CT, PD-1 positive TILs predicted DFS and CD3 and CD8 positive T cells as well as PD-1 positive TILs predicted OS. Survival analysis based on virtual TMA showed no impact on DFS or OS. CONCLUSION: Spatial tumor heterogeneity might result in inadequate quantification of immune marker expression; however, if using a TMA, 6 cores per tumor area and patient sample represent comparable amounts of T cell densities to those quantified on full tissue sections. Consistently, the tissue area used for immune marker quantification represents a crucial factor for the evaluation of prognostic and predictive biomarker potential.

PDGFRα and αSMA mark two distinct mesenchymal cell populations involved in parenchymal and vascular remodeling in pulmonary fibrosis.

Pulmonary fibrosis is characterized by pronounced collagen deposition and myofibroblast expansion, whose origin and plasticity remain elusive. We utilized a fate-mapping approach to investigate α-smooth muscle actin (αSMA)+ and platelet-derived growth factor receptor α (PDGFRα)+ cells in two lung fibrosis models, complemented by cell type-specific next-generation sequencing and investigations on human lungs. Our data revealed that αSMA+ and PDGFRα+ cells mark two distinct mesenchymal lineages with minimal transdifferentiation potential during lung fibrotic remodeling. Parenchymal and perivascular fibrotic regions were populated predominantly with PDGFRα+ cells expressing collagen, while αSMA+ cells in the parenchyma and vessel wall showed variable expression of collagen and the contractile protein desmin. The distinct gene expression profile found in normal conditions was retained during pathologic remodeling. Cumulatively, our findings identify αSMA+ and PDGFRα+ cells as two separate lineages with distinct gene expression profiles in adult lungs. This cellular heterogeneity suggests that anti-fibrotic therapy should target diverse cell populations.

Bilateral lung transplantation on intraoperative extracorporeal membrane oxygenator: An observational study.

OBJECTIVE: Intraoperative extracorporeal membrane oxygenation (ECMO) is usually reserved to support patients during complex lung transplantation. We hypothesized that a routine application of intraoperative ECMO in all patients improves primary graft function. METHODS: Patients receiving a bilateral lung transplantation between November 2016 and July 2018 at the Medical University of Vienna were included in this prospective, single-center observational study. All transplantations were uniformly performed on central venoarterial ECMO support, with the possibility to extend ECMO into the early postoperative period whenever graft function did not meet established quality criteria at the end of implantation. Primary graft dysfunction (PGD) grades were evaluated at 24, 48, and 72 hours after transplantation. Perioperative complications and survival outcome were assessed. RESULTS: A total of 159 patients were included in the study. At 24 hours post-transplantation, 38.4% (n = 61) of patients were already extubated, 48.4% (n = 77) were classified as PGD0, 4.4% (n = 7) as PGD1, 3.1% (n = 5) as PGD2, 2.5% (n = 4) as PGD3, and 3.1% (n = 5) were "ungradable" due to prophylactic postoperative prolongation of ECMO. At 72 hours after transplantation, 76.7% (n = 122) of the patients were extubated, as opposed to only 1.3% (n = 2) of patients classified as PGD3. The median time of mechanical ventilation was 29 hours (interquartile range, 17-58). The 90-day-mortality was 3.1%, and 2-year survival was 86%. CONCLUSIONS: Routine use of intraoperative ECMO resulted in excellent primary graft function and mid-term outcome in patients undergoing lung transplantation. To the best of our knowledge, the herein measured PGD rates are the lowest reported in the literature to date. Our results advocate a routine intraoperative use of ECMO in bilateral lung transplantation.

Inhibiting eicosanoid degradation exerts antifibrotic effects in a pulmonary fibrosis mouse model and human tissue.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a disease with high 5-year mortality and few therapeutic options. Prostaglandin (PG) E2 exhibits antifibrotic properties and is reduced in bronchoalveolar lavage from patients with IPF. 15-Prostaglandin dehydrogenase (15-PGDH) is the key enzyme in PGE2 metabolism under the control of TGF-ß and microRNA 218. OBJECTIVE: We sought to investigate the expression of 15-PGDH in IPF and the therapeutic potential of a specific inhibitor of this enzyme in a mouse model and human tissue. METHODS: In vitro studies, including fibrocyte differentiation, regulation of 15-PGDH, RT-PCR, and Western blot, were performed using peripheral blood from healthy donors and patients with IPF and A549 cells. Immunohistochemistry, immunofluorescence, 15-PGDH activity assays, and in situ hybridization as well as ex vivo IPF tissue culture experiments were done using healthy donor and IPF lungs. Therapeutic effects of 15-PGDH inhibition were studied in the bleomycin mouse model of pulmonary fibrosis. RESULTS: We demonstrate that 15-PGDH shows areas of increased expression in patients with IPF. Inhibition of this enzyme increases PGE2 levels and reduces collagen production in IPF precision cut lung slices and in the bleomycin model. Inhibitor-treated mice show amelioration of lung function, decreased alveolar epithelial cell apoptosis, and fibroblast proliferation. Pulmonary fibrocyte accumulation is also decreased by inhibitor treatment in mice, similar to PGE2 that inhibits fibrocyte differentiation from blood of healthy donors and patients with IPF. Finally, microRNA 218-5p, which is downregulated in patients with IPF, suppressed 15-PGDH expression in vivo and in vitro. CONCLUSIONS: These findings highlight the role of 15-PGDH in IPF and suggest 15-PGDH inhibition as a promising therapeutic approach.

Expression of FGFR1-4 in Malignant Pleural Mesothelioma Tissue and Corresponding Cell Lines and its Relationship to Patient Survival and FGFR Inhibitor Sensitivity.

Malignant pleural mesothelioma (MPM) is a devastating malignancy with limited therapeutic options. Fibroblast growth factor receptors (FGFR) and their ligands were shown to contribute to MPM aggressiveness and it was suggested that subgroups of MPM patients could benefit from FGFR-targeted inhibitors. In the current investigation, we determined the expression of all four FGFRs (FGFR1-FGFR4) by immunohistochemistry in tissue samples from 94 MPM patients. From 13 of these patients, we were able to establish stable cell lines, which were subjected to FGFR1-4 staining, transcript analysis by quantitative RT-PCR, and treatment with the FGFR inhibitor infigratinib. While FGFR1 and FGFR2 were widely expressed in MPM tissue and cell lines, FGFR3 and FGFR4 showed more restricted expression. FGFR1 and FGFR2 showed no correlation with clinicopathologic data or patient survival, but presence of FGFR3 in 42% and of FGFR4 in 7% of patients correlated with shorter overall survival. Immunostaining in cell lines was more homogenous than in the corresponding tissue samples. Neither transcript nor protein expression of FGFR1-4 correlated with response to infigratinib treatment in MPM cell lines. We conclude that FGFR3 and FGFR4, but not FGFR1 or FGFR2, have prognostic significance in MPM and that FGFR expression is not sufficient to predict FGFR inhibitor response in MPM cell lines.