Publications by authors named "Erik Verbeken"

134 Publications

Lung Functioning and Inflammation in a Mouse Model of Systemic Juvenile Idiopathic Arthritis.

Front Immunol 2021 12;12:642778. Epub 2021 Mar 12.

Laboratory of Immunobiology, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.

Systemic juvenile idiopathic arthritis (sJIA) is an immune disorder characterized by fever, skin rash, arthritis and splenomegaly. Recently, increasing number of sJIA patients were reported having lung disease. Here, we explored lung abnormalities in a mouse model for sJIA relying on injection of IFN-γ deficient (IFN-γ KO) mice with complete Freund's adjuvant (CFA). Monitoring of lung changes during development of sJIA using microcomputer tomography revealed a moderate enlargement of lungs, a decrease in aerated and increase in non-aerated lung density. When lung function and airway reactivity to methacholine was assessed, gender differences were seen. While male mice showed an increased tissue hysteresivity, female animals were characterized by an increased airway hyperactivity, mirroring ongoing inflammation. Histologically, lungs of sJIA-like mice showed subpleural and parenchymal cellular infiltrates and formation of small granulomas. Flow cytometric analysis identified immature and mature neutrophils, and activated macrophages as major cell infiltrates. Lung inflammation in sJIA-like mice was accompanied by augmented expression of IL-1β and IL-6, two target cytokines in the treatment of sJIA. The increased expression of granulocyte colony stimulating factor, a potent inducer of granulopoiesis, in lungs of mice was striking considering the observed neutrophilia in patients. We conclude that development of sJIA in a mouse model is associated with lung inflammation which is distinct to the lung manifestations seen in sJIA patients. Our observations however underscore the importance of monitoring lung disease during systemic inflammation and the model provides a tool to explore the underlying mechanism of lung pathology in an autoinflammatory disease context.
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http://dx.doi.org/10.3389/fimmu.2021.642778DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996094PMC
March 2021

Involvement of Innate Lymphoid Cells and Dendritic Cells in a Mouse Model of Chemical-induced Asthma.

Allergy Asthma Immunol Res 2021 Mar;13(2):295-311

Centre for Environment and Health, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium.

Purpose: Exposure to low concentrations of toluene diisocyanate (TDI) leads to immune-mediated chemical-induced asthma. The role of the adaptive immune system has already been thoroughly investigated; nevertheless, the involvement of innate immune cells in the pathophysiology of chemical-induced asthma is still unresolved. The aim of the study is to investigate the role of innate lymphoid cells (ILCs) and dendritic cells (DCs) in a mouse model for chemical-induced asthma.

Methods: On days 1 and 8, BALB/c mice were dermally treated (20 μL/ear) with 0.5% TDI or the vehicle acetone olive oil (AOO; 2:3). On days 15, 17, 19, 22 and 24, the mice received an oropharyngeal challenge with 0.01% TDI or AOO (1:4). One day after the last challenge, airway hyperreactivity (AHR) to methacholine was assessed, followed by an evaluation of pulmonary inflammation and immune-related parameters, including the cytokine pattern in bronchoalveolar lavage fluid, lymphocyte subpopulations of the lymph nodes and their cytokine production profile, blood immunoglobulins and DC and ILC subpopulations in the lungs.

Results: Both DC and ILC2 were recruited to the lungs after multiple airway exposures to TDI, regardless of the prior dermal sensitization. However, prior dermal sensitization with TDI alone results in AHR and predominant eosinophilic airway inflammation, accompanied by a typical type 2 helper T (Th2) cytokine profile.

Conclusions: TDI-induced asthma is mediated by a predominant type 2 immune response, with the involvement of adaptive Th2 cells. However, from our study we suggest that the innate ILC2 cells are important additional players in the development of TDI-induced asthma.
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http://dx.doi.org/10.4168/aair.2021.13.2.295DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7840869PMC
March 2021

Free Airway C4d after Lung Transplantation - A Quantitative Analysis of Bronchoalveolar Lavage Fluid.

Transpl Immunol 2021 02 17;64:101352. Epub 2020 Nov 17.

Department of Chronic Diseases, Metabolism & Ageing (CHROMETA), Laboratory of Respiratory Diseases & Thoracic Surgery (BREATHE), UZ/KU Leuven, Leuven, Belgium. Electronic address:

In recent years, the utility of vascular complement factor 4d (C4d) deposition as diagnostic tool for antibody mediated rejection (AMR) after lung transplantation, has become a controversial issue. We aimed to pinpoint the problematic nature of C4d as biomarker with a simple experiment. We quantified C4d in broncho-alveolar lavage (BAL) of lung transplant patients with diverse post-transplant complications in 3 different settings of clinically clear cases of: 1/ chronic lung allograft dysfunction (CLAD); 2/ acute complications acute rejection (AR), lymphocytic bronchiolitis (LB), antibody-mediated rejection (AMR) and respiratory infection (INF); 3/ patients with parallel C4d immunostaining and Anti-HLA. All groups were compared to BAL of stable patients. C4d was measured via standard ELISA. C4d was increased in CLAD, predominantly in RAS (p = 0.0026) but not in BOS (p = 0.89). C4d was increased in all acute events, AR (p = 0.0025), LB (p < 0.0001), AMR (p = 0.0034), infections (p < 0.0001). In patients with parallel C4d immunostaining and serum HLA antibodies, C4d was increased in C4d-/HLA- (p = 0.0011); C4d-/HLA+ (p = 0.013); HLA+/C4d + (p = 0.0081). A correlation of systemic C-reactive protein (CRP) with C4d was found in all patients (r = 0.49; p < 0.0001). We hypothesize that free C4d in BAL may only be representative of a general immune response in the transplanted lung.
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http://dx.doi.org/10.1016/j.trim.2020.101352DOI Listing
February 2021

Common occurrence of Belerina virus, a novel paramyxovirus found in Belgian hedgehogs.

Sci Rep 2020 11 9;10(1):19341. Epub 2020 Nov 9.

Laboratory of Clinical and Epidemiological Virology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven-University of Leuven, Herestraat 49, Box 1040, 3000, Leuven, Belgium.

Common or European hedgehogs can be found throughout Western Europe. They are known carriers of a variety of parasitic and bacterial pathogens, and have also been shown to carry several viruses, including morbilli-like paramyxoviruses, although the pathogenic and zoonotic potential of some of these viruses has yet to be determined. We report here the discovery of a novel paramyxovirus in Belgian hedgehogs, named Belerina virus. The virus was detected by nanopore sequencing of RNA isolated from hedgehog tissue. Out of 147 animals screened in this study, 57 tested positive for Belerina virus (39%), indicating a high prevalence of this virus in the Belgian hedgehog population. Based on its divergence from other known paramyxovirus species, Belerina virus is thought to represent a new species in the family Paramyxoviridae. Phylogenetic analysis groups Belerina virus together with the bat-borne Shaan virus within the genus Jeilongvirus, although expanding the tree with partial genomes shows Belerina virus forming a separate subclade within this genus, alongside a yet-unnamed paramyxovirus isolated from a greater tube-nosed bat. In summary, we discuss the complete genome sequence of Belerina virus, a putative new paramyxovirus species commonly found in Belgian hedgehogs.
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http://dx.doi.org/10.1038/s41598-020-76419-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7653956PMC
November 2020

Small airway loss in the physiologically ageing lung: a cross-sectional study in unused donor lungs.

Lancet Respir Med 2021 02 5;9(2):167-174. Epub 2020 Oct 5.

Laboratory of Respiratory Diseases and Thoracic Surgery (BREATHE), Department of Chronic diseases, Metabolism and Aging (CHROMETA), KU Leuven, Leuven, Belgium.

Background: Physiological lung ageing is associated with a gradual decline in dynamic lung volumes and a progressive increase in residual volume due to diminished elastic recoil of the lung, loss of alveolar tissue, and lower chest wall compliance. However, the effects of ageing on the small airways (ie, airways <2·0 mm in diameter) remain largely unknown. By using a combination of ex-vivo conventional CT (resolution 1 mm), whole lung micro-CT (resolution 150 μm), and micro-CT of extracted cores (resolution 10 μm), we aimed to provide a multiresolution assessment of the small airways in lung ageing in a large cohort of never smokers.

Methods: For this cross-sectional study, we included donor lungs collected from 32 deceased never-smoking donors (age range 16-83 years). Ex-vivo CT and whole lung high-resolution CT (micro-CT) were used to determine total airway numbers, stratified by airway diameter. Micro-CT was used to assess the number, length, and diameter of terminal bronchioles (ie, the last generation of conducting airways); mean linear intercept; and surface density in four lung tissue cores from each lung, extracted using a uniform sampling approach. Regression β coefficients are calculated using linear regression and polynomial models.

Findings: Ex-vivo CT analysis showed an age-dependent decrease in the number of airways of diameter 2·0 mm to less than 2·5 mm (β coefficient per decade -0·119, 95% CI -0·193 to -0·045; R=0·29) and especially in airways smaller than 2·0 mm in diameter (-0·158, -0·233 to -0·084; R=0·47), between 30 and 80 years of age, but not of the larger (≥2·5 mm) diameter airways (-0·00781, -0·04409 to 0·02848; R=0·0007). In micro-CT analysis of small airways, the total number of terminal bronchioles per lung increased until the age of 30 years, after which an almost linear decline in the number of terminal bronchioles was observed (β coefficient per decade -2035, 95% CI -2818 to -1252; R=0·55), accompanied by a non-significant increase in alveolar airspace size (6·44, -0·57 to 13·45, R=0·10). Moreover, this decrease in terminal bronchioles was associated with the age-related decline of pulmonary function predicted by healthy reference values.

Interpretation: Loss of terminal bronchioles is an important structural component of age-related decline in pulmonary function of healthy, non-smoking individuals.

Funding: Research Foundation-Flanders, KU Leuven, Parker B Francis Foundation, UGent, Canadian Institutes for Health.
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http://dx.doi.org/10.1016/S2213-2600(20)30324-6DOI Listing
February 2021

Longitudinal micro-computed tomography-derived biomarkers quantify non-resolving lung fibrosis in a silicosis mouse model.

Sci Rep 2020 09 30;10(1):16181. Epub 2020 Sep 30.

Department of Imaging and Pathology, Biomedical MRI/MoSAIC, KU Leuven, Leuven, Belgium.

In spite of many compounds identified as antifibrotic in preclinical studies, pulmonary fibrosis remains a life-threatening condition for which highly effective treatment is still lacking. Towards improving the success-rate of bench-to-bedside translation, we investigated in vivo µCT-derived biomarkers to repeatedly quantify experimental silica-induced pulmonary fibrosis and assessed clinically relevant readouts up to several months after silicosis induction. Mice were oropharyngeally instilled with crystalline silica or saline and longitudinally monitored with respiratory-gated-high-resolution µCT to evaluate disease onset and progress using scan-derived biomarkers. At weeks 1, 5, 9 and 15, we assessed lung function, inflammation and fibrosis in subsets of mice in a cross-sectional manner. Silica-instillation increased the non-aerated lung volume, corresponding to onset and progression of inflammatory and fibrotic processes not resolving with time. Moreover, total lung volume progressively increased with silicosis. The volume of healthy, aerated lung first dropped then increased, corresponding to an acute inflammatory response followed by recovery into lower elevated aerated lung volume. Imaging results were confirmed by a significantly decreased Tiffeneau index, increased neutrophilic inflammation, increased IL-13, MCP-1, MIP-2 and TNF-α concentration in bronchoalveolar lavage fluid, increased collagen content and fibrotic nodules. µCT-derived biomarkers enable longitudinal evaluation of early onset inflammation and non-resolving pulmonary fibrosis as well as lung volumes in a sensitive and non-invasive manner. This approach and model of non-resolving lung fibrosis provides quantitative assessment of disease progression and stabilization over weeks and months, essential towards evaluation of fibrotic disease burden and antifibrotic therapy evaluation in preclinical studies.
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http://dx.doi.org/10.1038/s41598-020-73056-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527558PMC
September 2020

From Mouse to Man and Back: Closing the Correlation Gap between Imaging and Histopathology for Lung Diseases.

Diagnostics (Basel) 2020 Aug 26;10(9). Epub 2020 Aug 26.

Department of Imaging and Pathology, KU Leuven, University of Leuven, 3000 Leuven, Belgium.

Lung diseases such as fibrosis, asthma, cystic fibrosis, infection and cancer are life-threatening conditions that slowly deteriorate quality of life and for which our diagnostic power is high, but our knowledge on etiology and/or effective treatment options still contains important gaps. In the context of day-to-day practice, clinical and preclinical studies, clinicians and basic researchers team up and continuously strive to increase insights into lung disease progression, diagnostic and treatment options. To unravel disease processes and to test novel therapeutic approaches, investigators typically rely on end-stage procedures such as serum analysis, cyto-/chemokine profiles and selective tissue histology from animal models. These techniques are useful but provide only a snapshot of disease processes that are essentially dynamic in time and space. Technology allowing evaluation of live animals repeatedly is indispensable to gain a better insight into the dynamics of lung disease progression and treatment effects. Computed tomography (CT) is a clinical diagnostic imaging technique that can have enormous benefits in a research context too. Yet, the implementation of imaging techniques in laboratories lags behind. In this review we want to showcase the integrated approaches and novel developments in imaging, lung functional testing and pathological techniques that are used to assess, diagnose, quantify and treat lung disease and that may be employed in research on patients and animals. Imaging approaches result in often novel anatomical and functional biomarkers, resulting in many advantages, such as better insight in disease progression and a reduction in the numbers of animals necessary. We here showcase integrated assessment of lung disease with imaging and histopathological technologies, applied to the example of lung fibrosis. Better integration of clinical and preclinical imaging technologies with pathology will ultimately result in improved clinical translation of (therapy) study results.
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http://dx.doi.org/10.3390/diagnostics10090636DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7554749PMC
August 2020

Cobalt exposure via skin alters lung immune cells and enhances pulmonary responses to cobalt in mice.

Am J Physiol Lung Cell Mol Physiol 2020 10 29;319(4):L641-L651. Epub 2020 Jul 29.

Centre for Environment and Health, Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium.

Cobalt has been associated with allergic contact dermatitis and occupational asthma. However, the link between skin exposure and lung responses to cobalt is currently unknown. We investigated the effect of prior dermal sensitization to cobalt on pulmonary physiological and immunological responses after subsequent challenge with cobalt via the airways. BALB/c mice received epicutaneous applications (25 μL/ear) with 5% CoCl6HO (Co) or the vehicle (Veh) dimethyl sulfoxide (DMSO) twice; they then received oropharyngeal challenges with 0.05% CoCl6HO or saline five times, thereby obtaining four groups: Veh/Veh, Co/Veh, Veh/Co, and Co/Co. To detect early respiratory responses noninvasively, we performed sequential in vivo microcomputed tomography (µCT). One day after the last challenge, we assessed airway hyperreactivity (AHR) to methacholine, inflammation in bronchoalveolar lavage (BAL), innate lymphoid cells (ILCs) and dendritic cells (DCs) in the lungs, and serum IgE. Compared with the Veh/Veh group, the Co/Co group showed increased µCT-derived lung response, increased AHR to methacholine, mixed neutrophilic and eosinophilic inflammation, elevated monocyte chemoattractant protein-1 (MCP-1), and elevated keratinocyte chemoattractant (KC) in BAL. Flow cytometry in the Co/Co group demonstrated increased DC, type 1 and type 2 conventional DC (cDC1/cDC2), monocyte-derived DC, increased ILC , and natural cytotoxicity receptorILC . The Veh/Co group showed only increased AHR to methacholine and elevated MCP-1 in BAL, whereas the Co/Veh group showed increased cDC1 and ILC2 in lung. We conclude that dermal sensitization to cobalt may increase the susceptibility of the lungs to inhaling cobalt. Mechanistically, this enhanced susceptibility involves changes in pulmonary DCs and ILCs.
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http://dx.doi.org/10.1152/ajplung.00265.2020DOI Listing
October 2020

Quantitative analysis of airway obstruction in lymphangioleiomyomatosis.

Eur Respir J 2020 07 2;56(1). Epub 2020 Jul 2.

Respiratory Diseases, Dept of Chronic Diseases, Metabolism and Aging, KU Leuven, Leuven, Belgium.

Lymphangioleiomyomatosis (LAM) is a rare, cystic lung disease with progressive pulmonary function loss caused by progressively proliferating LAM cells. The degree of airway obstruction has not been well investigated within the pathogenesis of LAM.Using a combination of computed tomography (CT), microCT and histology, the site and nature of airway obstruction in LAM explant lungs was compared with matched control lungs (n=5 each). The total number of airways per generation, total airway counts, terminal bronchioles number and surface density were compared in LAM control. CT analysis demonstrated a reduced number of airways from generation 7 on (p<0.0001) in LAM compared with control, whereas whole-lung microCT analysis confirmed the three- to four-fold reduction in the number of airways. Specimen microCT analysis further demonstrated a four-fold decrease in the number of terminal bronchioles (p=0.0079) and a decreased surface density (p=0.0079). Serial microCT and histology images directly showed the loss of functional airways by collapse of airways on the cysts and filling of the airway by exudate.LAM lungs show a three- to four-fold decrease in the number of (small) airways, caused by cystic destruction which is the likely culprit for the progressive loss of pulmonary function.
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http://dx.doi.org/10.1183/13993003.01965-2019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7330132PMC
July 2020

Small airways pathology in idiopathic pulmonary fibrosis: a retrospective cohort study.

Lancet Respir Med 2020 06 13;8(6):573-584. Epub 2020 Feb 13.

University of British Columbia, Department of Pathology and Center for Heart and Lung Innovation at St Paul's Hospital, Vancouver, BC, Canada. Electronic address:

Background: The observation that patients with idiopathic pulmonary fibrosis (IPF) can have higher than normal expiratory flow rates at low lung volumes led to the conclusion that the airways are spared in IPF. This study aimed to re-examine the hypothesis that airways are spared in IPF using a multiresolution imaging protocol that combines multidetector CT (MDCT), with micro-CT and histology.

Methods: This was a retrospective cohort study comparing explanted lungs from patients with severe IPF treated by lung transplantation with a cohort of unused donor (control) lungs. The donor control lungs had no known lung disease, comorbidities, or structural lung injury, and were deemed appropriate for transplantation on review of the clinical files. The diagnosis of IPF in the lungs from patients was established by a multidisciplinary consensus committee according to existing guidelines, and was confirmed by video-assisted thoracic surgical biopsy or by pathological examination of the contralateral lung. The control and IPF groups were matched for age, sex, height, and bodyweight. Samples of lung tissue were compared using the multiresolution imaging approach: a cascade of clinical MDCT, micro-CT, and histological imaging. We did two experiments: in experiment 1, all the lungs were randomly sampled; in experiment 2, samples were selected from regions of minimal and established fibrosis. The patients and donors were recruited from the Katholieke Universiteit Leuven (Leuven, Belgium) and the University of Pennsylvania Hospital (Philadelphia, PA, USA). The study took place at the Katholieke Universiteit Leuven, and the University of British Columbia (Vancouver, BC, Canada).

Findings: Between Oct 5, 2009, and July 22, 2016, explanted lungs from patients with severe IPF (n=11), were compared with a cohort of unused donor (control) lungs (n=10), providing 240 samples of lung tissue for comparison using the multiresolution imaging approach. The MDCT specimen scans show that the number of visible airways located between the ninth generation (control 69 [SD 22] versus patients with IPF 105 [33], p=0·0023) and 14th generation (control 9 [6] versus patients with IPF 49 [28], p<0·0001) of airway branching are increased in patients with IPF, which we show by micro-CT is due to thickening of their walls and distortion of their lumens. The micro-CT analysis showed that compared with healthy (control) lung anatomy (mean 5·6 terminal bronchioles per mL [SD 1·6]), minimal fibrosis in IPF tissue was associated with a 57% loss of the terminal bronchioles (mean 2·4 terminal bronchioles per mL [SD 1·0]; p<0·0001), the appearance of fibroblastic foci, and infiltration of the tissue by inflammatory immune cells capable of forming lymphoid follicles. Established fibrosis in IPF tissue had a similar reduction (66%) in the number of terminal bronchioles (mean 1·9 terminal bronchioles per mL [SD 1·4]; p<0·0001) and was dominated by increased airspace size, Ashcroft fibrosis score, and volume fractions of tissue and collagen.

Interpretation: Small airways disease is a feature of IPF, with significant loss of terminal bronchioles occuring within regions of minimal fibrosis. On the basis of these findings, we postulate that the small airways could become a potential therapeutic target in IPF.

Funding: Katholieke Universiteit Leuven, US National Institutes of Health, BC Lung Association, and Genentech.
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http://dx.doi.org/10.1016/S2213-2600(19)30356-XDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7292784PMC
June 2020

Identification and characterization of chronic lung allograft dysfunction patients with mixed phenotype: A single-center study.

Clin Transplant 2020 02 28;34(2):e13781. Epub 2020 Jan 28.

Lung Transplant Unit, Department of Chronic diseases, Metabolism and Aging, KU Leuven, Leuven, Belgium.

Rationale: Patients can change chronic lung allograft dysfunction (CLAD) phenotype, especially from BOS to mixed phenotype. Our aim was to further characterize these patients.

Method: Mixed CLAD was defined as a restrictive physiology with persistent CT opacities, after initial bronchiolitis obliterans syndrome (BOS) diagnosis. The incidence, prognosis, pulmonary function, radiology, pathology, and airway inflammation were compared between patients with restrictive allograft syndrome (RAS) and mixed CLAD.

Result: A total of 268 (44%) patients developed CLAD of which 47 (18%) were diagnosed with RAS "ab initio," 215 (80%) with BOS, and 6 (2%) an undefined phenotype. Twenty-five patients developed a mixed CLAD phenotype (24 BOS to mixed and 1 RAS to mixed). Survival after mixed phenotype diagnosis was comparable (P = .39) to RAS. More emphysema patients developed a mixed phenotype (P = .020) compared to RAS ab initio, while mixed CLAD patients had a lower FEV (P < .0001) and FEV /FVC (P = .0002) at diagnosis compared to RAS ab initio. CT scans in patients with the mixed phenotype demonstrated apical predominance of the opacities (P = .0034) with pleuroparenchymal fibroelastosis on histopathology.

Conclusion: We further characterized patients with a mixed phenotype of CLAD. Although the survival after diagnosis was comparable to RAS ab initio patients, there was a difference in demography, pulmonary function, radiology, and pathology.
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http://dx.doi.org/10.1111/ctr.13781DOI Listing
February 2020

An Integrated Gene Expression Landscape Profiling Approach to Identify Lung Tumor Endothelial Cell Heterogeneity and Angiogenic Candidates.

Cancer Cell 2020 01;37(1):21-36.e13

Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology and Leuven Cancer Institute (LKI), KU Leuven, VIB Center for Cancer Biology, Leuven 3000, Belgium; State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, Guangdong, China. Electronic address:

Heterogeneity of lung tumor endothelial cell (TEC) phenotypes across patients, species (human/mouse), and models (in vivo/in vitro) remains poorly inventoried at the single-cell level. We single-cell RNA (scRNA)-sequenced 56,771 endothelial cells from human/mouse (peri)-tumoral lung and cultured human lung TECs, and detected 17 known and 16 previously unrecognized phenotypes, including TECs putatively regulating immune surveillance. We resolved the canonical tip TECs into a known migratory tip and a putative basement-membrane remodeling breach phenotype. Tip TEC signatures correlated with patient survival, and tip/breach TECs were most sensitive to vascular endothelial growth factor blockade. Only tip TECs were congruent across species/models and shared conserved markers. Integrated analysis of the scRNA-sequenced data with orthogonal multi-omics and meta-analysis data across different human tumors, validated by functional analysis, identified collagen modification as a candidate angiogenic pathway.
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http://dx.doi.org/10.1016/j.ccell.2019.12.001DOI Listing
January 2020

Programmed death-ligand 1 expression influenced by tissue sample size. Scoring based on tissue microarrays' and cross-validation with resections, in patients with, stage I-III, non-small cell lung carcinoma of the European Thoracic Oncology Platform Lungscape cohort.

Mod Pathol 2020 05 18;33(5):792-801. Epub 2019 Nov 18.

Department of Medical Oncology and Hematology, University Hospital Zurich, Zurich, Switzerland.

PD-L1, as assessed by immunohistochemistry, is a predictive biomarker for immuno-oncology treatment in lung cancer. Different scoring methods have been used to assess its status, resulting in a wide range of positivity rates. We use the European Thoracic Oncology Platform Lungscape non-small cell lung carcinoma cohort to explore this issue. PD-L1 expression was assessed via immunohistochemistry on tissue microarrays (up to four cores per case), using the DAKO 28-8 immunohistochemistry assay, following a two-round external quality assessment procedure. All samples were analyzed under the same protocol. Cross-validation of scoring between tissue microarray and whole sections was performed in 10% randomly selected samples. Cutoff points considered: ≥1, 50 (primarily), and 25%. At the two external quality assessment rounds, tissue microarray scoring agreement rates between pathologists were: 73% and 81%. There were 2008 cases with valid immunohistochemistry tissue microarray results (50% all cores evaluable). Concordant cases at 1, 25, and 50% were: 85, 91, and 93%. Tissue microarray core results were identical for 70% of cases. Sensitivity of the tissue microarray method for 1, 25, and 50% was: 80, 78, and 79% (specificity: 90, 95, 98%). Complete agreement between tissue microarrays and whole sections was achieved for 60% of the cases. Highest sensitivity rates for 1% and 50% cutoffs were detected for higher number of cores. Underestimation of PD-L1 expression on small samples is more common than overestimation. We demonstrated that classification of PD-L1 on small biopsy samples does not represent the overall expression of PD-L1 in all non-small cell cancer carcinoma cases, although the majority of cases are 'correctly' classified. In future studies, sampling more and larger biopsies, recording the biopsy size and tumor load may permit further refinement, increasing predictive accuracy.
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http://dx.doi.org/10.1038/s41379-019-0383-9DOI Listing
May 2020

A robust human norovirus replication model in zebrafish larvae.

PLoS Pathog 2019 09 19;15(9):e1008009. Epub 2019 Sep 19.

KU Leuven-Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium.

Human noroviruses (HuNoVs) are the most common cause of foodborne illness, with a societal cost of $60 billion and 219,000 deaths/year. The lack of robust small animal models has significantly hindered the understanding of norovirus biology and the development of effective therapeutics. Here we report that HuNoV GI and GII replicate to high titers in zebrafish (Danio rerio) larvae; replication peaks at day 2 post infection and is detectable for at least 6 days. The virus (HuNoV GII.4) could be passaged from larva to larva two consecutive times. HuNoV is detected in cells of the hematopoietic lineage and the intestine, supporting the notion of a dual tropism. Antiviral treatment reduces HuNoV replication by >2 log10, showing that this model is suited for antiviral studies. Zebrafish larvae constitute a simple and robust replication model that will largely facilitate studies of HuNoV biology and the development of antiviral strategies.
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http://dx.doi.org/10.1371/journal.ppat.1008009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752765PMC
September 2019

Intra-host emergence of an enterovirus A71 variant with enhanced PSGL1 usage and neurovirulence.

Emerg Microbes Infect 2019 ;8(1):1076-1085

a KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy , Leuven , Belgium.

Enterovirus A71 (EV-A71) is one of the main causative agents of hand-foot-and-mouth disease and is occasionally associated with severe neurological complications. EV-A71 pathophysiology is poorly understood due to the lack of small animal models that robustly support viral replication in relevant organs/tissues. Here, we show that adult severe combined immune-deficient (SCID) mice can serve as an EV-A71 infection model to study neurotropic determinants and viral tropism. Mice inoculated intraperitoneally with an EV-A71 clinical isolate had an initial infection of the lung compartment, followed by neuroinvasion and infection of (motor)neurons, resulting in slowly progressing paralysis of the limbs. We identified a substitution (V135I) in the capsid protein VP2 as a key requirement for neurotropism. This substitution was also present in a mouse-adapted variant, obtained by passaging the clinical isolate in the brain of one-day-old mice, and induced exclusive neuropathology and rapid paralysis, confirming its role in neurotropism. Finally, we showed that this residue enhances the capacity of EV-A71 to use mouse PSGL1 for viral entry. Our data reveal that EV-A71 initially disseminates to the lung and identify viral and host determinants that define the neurotropic character of EV-A71, pointing to a hitherto understudied role of PSGL1 in EV-A71 tropism and neuropathology.
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http://dx.doi.org/10.1080/22221751.2019.1644142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6711088PMC
November 2019

Dermal exposure determines the outcome of repeated airway exposure in a long-term chemical-induced asthma-like mouse model.

Toxicology 2019 06 6;421:84-92. Epub 2019 May 6.

Centre for Environment and Health, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium. Electronic address:

Background: Exposure to diisocyanates is an important cause of occupational asthma (OA) in the industrialized world. Since OA occurs after long-term exposure to diisocyanates, we developed a chronic mouse model of chemical-induced asthma where toluene diisocyanate (TDI) was administered at two different exposure sites.

Objectives: Evaluating the effect of long-term respiratory isocyanate exposure - with or without prior dermal exposure- on sensitization, inflammatory responses and airway hyperreactivity (AHR).

Methods: On days 1 and 8, BALB/c mice were dermally treated (20 μl/ear) with 0.5% 2,4-toluene diisocyanate TDI or the vehicle acetone olive oil (AOO) (3:2). Starting from day 15, mice received intranasal instillations with 0.1% TDI of vehicle five times in a week, for five successive weeks. One day after the last instillation airway hyperreactivity (AHR) to methacholine was assessed, followed by an evaluation of pulmonary inflammation and structural lung changes. Immune-related parameters were assessed in the lungs (BAL and tissue), blood, cervical- and auricular lymph nodes.

Results: Mice repeatedly intranasally exposed to TDI showed systemic sensitization and a mixed Th1/Th2 type immune response, without the presence of AHR. However, when mice are first dermally sensitized with TDI, followed by repeated intranasal TDI challenges, this results in a pronounced Th2 response and AHR.

Conclusion: Dermal exposure to TDI determines airway hyperreactivity after repeated airway exposure to TDI.
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http://dx.doi.org/10.1016/j.tox.2019.05.001DOI Listing
June 2019

Alveolar Septal Widening as an "Alert" Signal to Look Into Lung Antibody-mediated Rejection: A Multicenter Pilot Study.

Transplantation 2019 11;103(11):2440-2447

Department of Histopathology, Papworth Hospital NHS Trust, Cambridge, United Kingdom.

Background: Antibody-mediated rejection (AMR) plays an important role in allograft dysfunction. Acute lung injury (ALI), endotheliitis, capillary inflammation, and C4d positivity have been described as morphological features conventionally associated with lung AMR. A multidisciplinary, international task force reviewed AMR cases in the context of four face-to-face meetings. Septal widening was a frequent, striking histological feature recognized first and easily at low-power magnification. This study aimed to evaluate whether septal widening could represent an "alert" signal for AMR.

Methods: Following the face-to-face meetings that enabled the classification of cases as AMR or non-AMR, morphometry was performed on biopsies from 48 recipients with definite, probable or possible AMR, 31 controls (negative for any posttransplant injury) and 10 patients with nonimmune-related ALI.

Results: Mean alveolar septal thickness was greater in AMR patients than in controls (P < 0.001). Septal thickness was not significantly different between AMR-ALI and non-AMR-ALI. Unexpectedly septal widening was the only histological change detected in some cases with probable or possible AMR that lacked the histological lesions conventionally associated with AMR. The thickness in these cases was similar to that observed in AMR cases with more severe histological injury such as ALI or neutrophilic capillaritis.

Conclusions: Our data suggest that, even if unspecific as the other lesions conventionally associated with AMR, septal widening may represent an "alert" signal to look into lung AMR. A larger prospective study is mandatory to confirm the potential value of septal widening in the multidisciplinary approach of AMR.
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http://dx.doi.org/10.1097/TP.0000000000002688DOI Listing
November 2019

The pleural mesothelium and transforming growth factor-β pathways in restrictive allograft syndrome: A pre-clinical investigation.

J Heart Lung Transplant 2019 05 6;38(5):570-579. Epub 2019 Feb 6.

Leuven Lung Transplant Group, Department of Chronic Diseases, Metabolism & Ageing, KU Leuven, Leuven, Belgium. Electronic address:

Background: Chronic lung allograft dysfunction (CLAD) hampers long-term survival after lung transplantation. Common fibrosis-related mechanisms in idiopathic pulmonary fibrosis and CLAD instigated the consideration of investigating the differential regulation of pleural mesothelium and transforming growth factor-β (TGF-β) in restrictive allograft syndrome (RAS).

Methods: TGF-β was assessed in bronchoalveolar lavage (BAL) fluid using enzyme-linked immunoassay and via immune staining of explant biopsies. To assess the role of the pleura, explanted bronchiolitis obliterans syndrome (BOS) and RAS lungs were compared using computed tomography scans, calretinin stainings, Western blot, and quantititative real-time PCR. Last, a pleural mesothelial cell line was used to assess mesothelial-to-mesenchymal transition and its inhibition.

Results: TGF-β was increased in BAL of RAS patients (p = 0.035), and was present in the (sub)pleural area of biopsies. Explanted RAS lungs demonstrated an increased volume fraction of pleura (p = 0.0004), a higher proportion of calretinin-positive stainings (p = 0.0032), and decreased E-cadherin (p = 0.019) and increased α-smooth muscle actin (p = 0.0089) mRNA expression and protein levels in isolated pleural tissue. Moreover, TGF-β stimulation of pleural mesothelial cells led to a phenotypical switch to mesenchymal cells, accompanied with an increased migratory capacity. Interleukin-1α was able to accentuate TGF-β‒induced mesothelial-to-mesenchymal transition. None of the tested drugs could inhibit mesothelial-to-mesenchymal transition at the used concentrations.

Conclusions: Our results support an interplay between TGF-β and the pleural mesothelium in the pathophysiology of RAS.
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http://dx.doi.org/10.1016/j.healun.2019.02.001DOI Listing
May 2019

Breast cancer cells rely on environmental pyruvate to shape the metastatic niche.

Nature 2019 04 27;568(7750):117-121. Epub 2019 Feb 27.

Laboratory of Cellular Metabolism and Metabolic Regulation, VIB-KU Leuven Center for Cancer Biology, VIB, Leuven, Belgium.

The extracellular matrix is a major component of the local environment-that is, the niche-that determines cell behaviour. During metastatic growth, cancer cells shape the extracellular matrix of the metastatic niche by hydroxylating collagen to promote their own metastatic growth. However, only particular nutrients might support the ability of cancer cells to hydroxylate collagen, because nutrients dictate which enzymatic reactions are active in cancer cells. Here we show that breast cancer cells rely on the nutrient pyruvate to drive collagen-based remodelling of the extracellular matrix in the lung metastatic niche. Specifically, we discovered that pyruvate uptake induces the production of α-ketoglutarate. This metabolite in turn activates collagen hydroxylation by increasing the activity of the enzyme collagen prolyl-4-hydroxylase (P4HA). Inhibition of pyruvate metabolism was sufficient to impair collagen hydroxylation and consequently the growth of breast-cancer-derived lung metastases in different mouse models. In summary, we provide a mechanistic understanding of the link between collagen remodelling and the nutrient environment in the metastatic niche.
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http://dx.doi.org/10.1038/s41586-019-0977-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6451642PMC
April 2019

Phenotypical diversity of airway morphology in chronic lung graft vs. host disease after stem cell transplantation.

Mod Pathol 2019 06 5;32(6):817-829. Epub 2019 Feb 5.

Lung Transplant Unit, Department of Chronic diseases, Metabolism and Aging, KU Leuven, Leuven, Belgium.

Pulmonary graft vs. host disease is a diverse and underestimated complication following allogenic hematopoietic stem cell transplantation. We aimed to compare the airway architecture with chronic lung allograft dysfunction post lung transplantation. Inflated explant lungs from graft vs. host disease patients were compared with lungs with chronic lung allograft dysfunction following lung transplantation, and control lungs using a combination of CT, microCT, and histology (n = 6 per group) and pathology in the (small) airways was further quantified and analyzed. Following allogenic hematopoietic stem cell transplantation, three patients presented as bronchiolitis obliterans syndrome and three patients showed interstitial changes and restriction. The CT analysis demonstrated a strong similarity between bronchiolitis obliterans syndrome after lung transplantation and post allogenic hematopoietic stem cell transplantation, evidenced by severe ( > 50%) airway obstruction from generation 9, with 70.8% of the airways ending in obstruction. Further analysis indicated that the airways either collapsed or accumulated matrix along a segment of the airway. In patients with restriction and interstitial changes following allogenic hematopoietic stem cell transplantation, the degree of airway obstruction was lower compared with bronchiolitis obliterans syndrome post allogenic hematopoietic stem cell transplantation, but similar to restrictive allograft syndrome post lung transplantation, showing a lower proportion of airway obstruction (20-35%), decreased number of terminal bronchioles per lung (p < 0.01), and parenchymal fibrosis. We observed similarities in the airway and parenchymal morphometric changes in lung graft vs. host disease and with chronic lung allograft dysfunction following lung transplantation, suggesting similar pathophysiological mechanisms.
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http://dx.doi.org/10.1038/s41379-019-0203-2DOI Listing
June 2019

Role of 18F-FDG PET/CT in Restrictive Allograft Syndrome After Lung Transplantation.

Transplantation 2019 04;103(4):823-831

Leuven Lung Transplant Unit, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium.

Background: Differential diagnosis of phenotypes of chronic lung allograft dysfunction (CLAD) remains troublesome. We hypothesized that F-fluorodeoxyglucose positron emission tomography with computed tomography (F-FDG PET/CT) may help in differential diagnosis of CLAD phenotypes, as it showed promising results regarding diagnosis and prognosis in interstitial lung diseases.

Methods: A monocentric, retrospective study was performed including all lung transplant recipients suffering from bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS) who underwent F-FDG PET/CT scan, in comparison with stable lung transplant recipients. Maximum standardized uptake value (SUVmax) was associated with pulmonary function and survival. Proof-of-concept microCT and glucose transporter-1 staining served as morphologic validation for regions with different SUVmax.

Results: Maximum standardized uptake value was higher in RAS (median, 2.6; n = 29) compared with BOS (median, 1.0; n = 15) and stable patients (median, 0.59; n = 8) (P < 0.0001). In RAS, high SUVmax was associated with worse survival after F-FDG PET/CT (P = 0.0004; hazard ratio, 1.82). Forced vital capacity at F-FDG PET/CT inversely correlated with SUVmax (R = -0.40, P = 0.03). MicroCT analysis revealed extensive fibrosis in regions of high SUVmax, with an increased number of glucose transporter-1-positive cells.

Conclusions: F-fluorodeoxyglucose positron emission tomography with CT may noninvasively differentiate RAS from BOS. RAS patients with areas of increased lung metabolism have worse outcome, demonstrating the potential use of F-FDG PET/CT during follow-up after lung transplantation.
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http://dx.doi.org/10.1097/TP.0000000000002393DOI Listing
April 2019

Phenotype molding of stromal cells in the lung tumor microenvironment.

Nat Med 2018 08 9;24(8):1277-1289. Epub 2018 Jul 9.

VIB Center for Cancer Biology, Leuven, Belgium.

Cancer cells are embedded in the tumor microenvironment (TME), a complex ecosystem of stromal cells. Here, we present a 52,698-cell catalog of the TME transcriptome in human lung tumors at single-cell resolution, validated in independent samples where 40,250 additional cells were sequenced. By comparing with matching non-malignant lung samples, we reveal a highly complex TME that profoundly molds stromal cells. We identify 52 stromal cell subtypes, including novel subpopulations in cell types hitherto considered to be homogeneous, as well as transcription factors underlying their heterogeneity. For instance, we discover fibroblasts expressing different collagen sets, endothelial cells downregulating immune cell homing and genes coregulated with established immune checkpoint transcripts and correlating with T-cell activity. By assessing marker genes for these cell subtypes in bulk RNA-sequencing data from 1,572 patients, we illustrate how these correlate with survival, while immunohistochemistry for selected markers validates them as separate cellular entities in an independent series of lung tumors. Hence, in providing a comprehensive catalog of stromal cells types and by characterizing their phenotype and co-optive behavior, this resource provides deeper insights into lung cancer biology that will be helpful in advancing lung cancer diagnosis and therapy.
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http://dx.doi.org/10.1038/s41591-018-0096-5DOI Listing
August 2018

Requirements for Successful Trachea Transplantation: A Study in the Rabbit Model.

Plast Reconstr Surg 2018 06;141(6):845e-856e

Leuven, Belgium.

Background: Although creating a tracheal tube de novo might appear straightforward, the first clinical applications have shown that reconstruction of long-segment tracheal defects remains challenging. In this study, the authors aimed to refine the baseline requirements of successful trachea transplantation by means of three proof-of-concept models in the rabbit.

Methods: In each model, one characteristic of a perfect tracheal transplant was eliminated. The first model was developed to map out the immunologic response of vascularized allogenic trachea, transplanted without immunosuppression (n = 6). The second model studied (1) the need for wrapping the transplant with a highly vascularized flap and (2) the source of angiogenesis after autologous trachea transplantation (n = 18). In the third model, the authors examined the importance of an inner epithelial covering (n = 12). All models were compared to a control group of heterotopically transplanted vascularized autologous tracheae (n = 6).

Results: Embedded in an avascular matrix, allogenic chondrocytes were protected from an overt immune response. Orthotopic transplantation without additional external vascular wrap was successful in a well-vascularized environment. Nonetheless, an external vascular source was essential to maintain viability of the construct. Epithelial covering was necessary to prevent secondary healing. Epithelial migration from the anastomoses or graft was not sufficient to cover long-segment defects.

Conclusions: These experiments provided ample evidence of the importance of baseline requirements when designing a tracheal transplant study. This study confirmed that different tracheal cell types possess different immunologic sensitivities. External revascularization, preferably in a two-stage procedure, and fast reepithelialization were both paramount to successful transplantation.
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http://dx.doi.org/10.1097/PRS.0000000000004429DOI Listing
June 2018

Irritant-induced asthma to hypochlorite in mice due to impairment of the airway barrier.

Arch Toxicol 2018 Apr 24;92(4):1551-1561. Epub 2018 Jan 24.

Centre for Environment and Health, Department of Public Health and Primary Care, University of Leuven, Herestraat 49 Mailbox 706, 3000, Leuven, Belgium.

Inhalation of commonly present irritants, such as chlorine and chlorine derivatives, can cause adverse respiratory effects, including irritant-induced asthma (IIA). We hypothesize that due to airway barrier impairment, exposure to hypochlorite (ClO) can result in airway hypersensitivity. C57Bl/6 mice received an intra-peritoneal (i.p.) injection of the airway damaging agent naphthalene (NA, 200 mg/kg body weight) or vehicle (mineral oil, MO). In vivo micro-computed tomography (CT) images of the lungs were acquired before and at regular time points after the i.p.

Treatment: After a recovery period of 14 days an intranasal (i.n.) challenge with 0.003% active chlorine (in ClO) or vehicle (distilled water, HO) was given, followed by assessment of the breathing frequency. One day later, pulmonary function, along with pulmonary inflammation was determined. Lung permeability was assessed by means of total broncho-alveolar lavage (BAL) protein content and plasma surfactant protein (SP)-D levels. In vivo micro-CT imaging revealed enlargement of the lungs and airways early after NA treatment, with a return to normal at day 14. When challenged i.n. with ClO, NA-pretreated mice immediately responded with a sensory irritant response. Twenty-four hours later, NA/ClO mice showed airway hyperreactivity (AHR), accompanied by a neutrophilic and eosinophilic inflammation. NA administration followed by ClO induced airway barrier impairment, as shown by increased BAL protein and plasma SP-D concentrations; histology revealed epithelial denudation. These data prove that NA-induced lung impairment renders the lungs of mice more sensitive to an airway challenge with ClO, confirming the hypothesis that incomplete barrier repair, followed by irritant exposure results in airway hypersensitivity.
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http://dx.doi.org/10.1007/s00204-018-2161-8DOI Listing
April 2018

The histomorphological spectrum of restrictive chronic lung allograft dysfunction and implications for prognosis.

Mod Pathol 2018 05 12;31(5):780-790. Epub 2018 Jan 12.

Lung Transplant Unit, Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium.

Chronic lung allograft dysfunction continues to be the main contributor to poor long-term allograft survival after lung transplantation. The restrictive phenotype of chronic lung allograft dysfunction carries a particularly poor prognosis. Little is known about the pathogenetic mechanisms involved in restrictive chronic lung allograft dysfunction. In this study, we performed histomorphological and immunohistochemical analysis of restrictive chronic lung allograft dysfunction lungs. Explant lung tissue from 21 restrictive chronic lung allograft dysfunction patients was collected and histopathologic patterns of rejection, fibrosis and vascular changes were scored after routine histochemical stains and additional immunohistochemistry for endothelial markers and C4d. In all, 75% of cases showed evidence of acute cellular rejection; lymphocytic bronchiolitis was absent in most lungs, whereas in 55% there was obliterative bronchiolitis. Almost half of the cases showed a pattern consistent with pleuroparenchymal fibro-elastosis (n=10), and a subset showed nonspecific interstitial pneumonia (n=5) or irregular emphysema (n=5). Fibrinous alveolar exudates were frequently seen in association with fibrosis (n=6), but no diffuse alveolar damage was found. Evidence of microvascular damage was present in most cases. An emphysematous pattern of fibrosis was associated with a better survival (P=0.0030), whereas fibrinous exudates were associated with a worse survival (P=0.0007). In addition to the previously described nonspecific interstitial pneumonia and pleuroparenchymal fibro-elastosis patterns in restrictive chronic lung allograft dysfunction, we are the first to describe a pattern of fibrosis-induced subpleural/paraseptal emphysema. This pattern confers a better survival, whereas fibrinous exudates are associated with a worse survival. We believe that our findings offer a pathogenetic theory for pleuroparenchymal fibro-elastosis in restrictive chronic lung allograft dysfunction, and show that restrictive chronic lung allograft dysfunction is an increasingly heterogeneous disease with presumably different mechanisms of subpattern formation.
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http://dx.doi.org/10.1038/modpathol.2017.180DOI Listing
May 2018

A lethal disease model for New World hantaviruses using immunosuppressed Syrian hamsters.

PLoS Negl Trop Dis 2017 Oct 27;11(10):e0006042. Epub 2017 Oct 27.

KU Leuven-University of Leuven, Department of Microbiology and Immunology, Laboratory of Clinical Virology, Zoonotic Infectious Diseases unit, Leuven, Belgium.

Background: Hantavirus, the hemorrhagic causative agent of two clinical diseases, is found worldwide with variation in severity, incidence and mortality. The most lethal hantaviruses are found on the American continent where the most prevalent viruses like Andes virus and Sin Nombre virus are known to cause hantavirus pulmonary syndrome. New World hantavirus infection of immunocompetent hamsters results in an asymptomatic infection except for Andes virus and Maporal virus; the only hantaviruses causing a lethal disease in immunocompetent Syrian hamsters mimicking hantavirus pulmonary syndrome in humans.

Methodology/principal Findings: Hamsters, immunosuppressed with dexamethasone and cyclophosphamide, were infected intramuscularly with different New World hantavirus strains (Bayou virus, Black Creek Canal virus, Caño Delgadito virus, Choclo virus, Laguna Negra virus, and Maporal virus). In the present study, we show that immunosuppression of hamsters followed by infection with a New World hantavirus results in an acute disease that precisely mimics both hantavirus disease in humans and Andes virus infection of hamsters.

Conclusions/ Significance: Infected hamsters showed specific clinical signs of disease and moreover, histological analysis of lung tissue showed signs of pulmonary edema and inflammation within alveolar septa. In this study, we were able to infect immunosuppressed hamsters with different New World hantaviruses reaching a lethal outcome with signs of disease mimicking human disease.
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http://dx.doi.org/10.1371/journal.pntd.0006042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5678717PMC
October 2017

Low-flow support of the chronic pressure-overloaded right ventricle induces reversed remodeling.

J Heart Lung Transplant 2018 01 29;37(1):151-160. Epub 2017 Sep 29.

Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium; Division of Experimental Cardiac Surgery, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium.

Background: Mechanical right ventricular (RV) support in pulmonary arterial hypertension patients has been feared to cause pulmonary hemorrhage and to be detrimental for the after-load-sensitive RV. Continuous low-flow pumps offer promise but remain insufficiently tested.

Methods: The pulmonary artery was banded in 20 sheep in this study. Eight weeks later, a Synergy micro-pump (HeartWare International, Framingham MA) was inserted in 10 animals, driving blood from the right atrium to the pulmonary artery. After magnetic resonance imaging, hemodynamics and RV pressure-volume loop data were recorded. Eight weeks later, RV function was assessed in the same way, followed by histologic analysis of the ventricular tissue.

Results: During the 8 weeks of support, RV volumes and central venous pressure decreased significantly, whereas RV contractility increased. Pulmonary artery pressure increased modestly, particularly its diastolic component. RV contribution to total right-sided cardiac output increased from 12 ± 12% to 41 ± 9% (p < 1 × 10). After pump inactivation, and compared with 8 weeks earlier, RV volumes had significantly decreased, tricuspid valve regurgitation had almost disappeared, and RV contractility had significantly increased, resulting in significantly increased RV forward power (0.25 ± 0.05 vs 0.16 ± 0.06 W, p = 0.014). Fulton index and RV myocyte size were significantly smaller, and without changes in fibrosis, when compared with controls.

Conclusions: Prolonged continuous low-flow RV mechanical support significantly unloads the chronic pressure-overloaded RV and improves cardiac output. After 8 weeks, RV hemodynamic recovery and reverse remodeling begin to occur, without increased fibrosis.
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http://dx.doi.org/10.1016/j.healun.2017.09.014DOI Listing
January 2018

Antiviral treatment efficiently inhibits chikungunya virus infection in the joints of mice during the acute but not during the chronic phase of the infection.

Antiviral Res 2018 01 25;149:113-117. Epub 2017 Sep 25.

University of Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, B-3000 Leuven, Belgium.

Favipiravir (T-705) is a broad spectrum antiviral which has been approved in Japan for the treatment of severe influenza virus infections. We reported earlier that favipiravir inhibits the in vitro replication of CHIKV and protects against disease progression in CHIKV-infected immunodeficient mice. We here explored whether favipiravir is also able to inhibit CHIKV replication in the joints of mice either when treatment is initiated during the acute or during the chronic phase of the infection. To this end, C57BL/6J mice were infected with CHIKV in the left hind footpad and treatment with favipiravir (300 mg/kg/day, orally) was either given from day 0 to day 3 post-infection (p.i.) or from day 49 to day 55 p.i. In the untreated mice, viral RNA was still detectable in the joints up to 98 days p.i., yet no infectious viral particles were observed in these tissues. The 4 days treatment during the acute phase of the infection resulted in complete inhibition of systemic viral spread. As a consequence, no viral RNA was detected in the non-inoculated feet in contrast to the situation in the untreated control mice. When treatment was initiated at day 49 p.i., no significant reduction in viral RNA levels in joints were noted as compared to the untreated control. Interestingly, when attempting to amplify by RT-PCR material corresponding to virus genome from the chronic phase samples, some parts of the genome, such as the viral polymerase gene could not be amplified. Collectively, these results suggest that the viral RNA detected in the joints during the chronic phase is likely defective, which also explains the lack of effect of a viral replication inhibitor.
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http://dx.doi.org/10.1016/j.antiviral.2017.09.016DOI Listing
January 2018

Forced expiration measurements in mouse models of obstructive and restrictive lung diseases.

Respir Res 2017 06 19;18(1):123. Epub 2017 Jun 19.

Center for Environment and Health, KU Leuven, Leuven, Belgium.

Background: Pulmonary function measurements are important when studying respiratory disease models. Both resistance and compliance have been used to assess lung function in mice. Yet, it is not always clear how these parameters relate to forced expiration (FE)-related parameters, most commonly used in humans. We aimed to characterize FE measurements in four well-established mouse models of lung diseases.

Method: Detailed respiratory mechanics and FE measurements were assessed concurrently in Balb/c mice, using the forced oscillation and negative pressure-driven forced expiration techniques, respectively. Measurements were performed at baseline and following increasing methacholine challenges in control Balb/c mice as well as in four disease models: bleomycin-induced fibrosis, elastase-induced emphysema, LPS-induced acute lung injury and house dust mite-induced asthma.

Results: Respiratory mechanics parameters (airway resistance, tissue damping and tissue elastance) confirmed disease-specific phenotypes either at baseline or following methacholine challenge. Similarly, lung function defects could be detected in each disease model by at least one FE-related parameter (FEV, FEF, FVC, FEV/FVC ratio and PEF) at baseline or during the methacholine provocation assay.

Conclusions: FE-derived outcomes in four mouse disease models behaved similarly to changes found in human spirometry. Routine combined lung function assessments could increase the translational utility of mouse models.
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http://dx.doi.org/10.1186/s12931-017-0610-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5477381PMC
June 2017