Cell-Free DNA and CXCL10 Derived from Bronchoalveolar Lavage Predict Lung Transplant Survival.

Standard methods for detecting chronic lung allograft dysfunction (CLAD) and rejection have poor sensitivity and specificity and have conventionally required bronchoscopies and biopsies. Plasma cell-free DNA (cfDNA) has been shown to be increased in various types of allograft injury in transplant recipients and CXCL10 has been reported to be increased in the lung tissue of patients undergoing CLAD. This study used a novel cfDNA and CXCL10 assay to evaluate the noninvasive assessment of CLAD phenotype and prediction of survival from bronchoalveolar lavage (BAL) fluid. A total of 60 BAL samples (20 with bronchiolitis obliterans (BOS), 20 with restrictive allograft syndrome (RAS), and 20 with stable allografts (STA)) were collected from 60 unique lung transplant patients; cfDNA and CXCL10 were measured by the ELISA-based KIT assay. Median cfDNA was significantly higher in BOS patients (6739 genomic equivalents (GE)/mL) versus STA (2920 GE/mL) and RAS (4174 GE/mL) (p < 0.01 all comparisons). Likelihood ratio tests revealed a significant association of overall survival with cfDNA (p = 0.0083), CXCL10 (p = 0.0146), and the interaction of cfDNA and CXCL10 (p = 0.023) based on multivariate Cox proportional hazards regression. Dichotomizing patients based on the median cfDNA level controlled for the mean level of CXCL10 revealed an over two-fold longer median overall survival time in patients with low levels of cfDNA. The KIT assay could predict allograft survival with superior performance compared with traditional biomarkers. These data support the pursuit of larger prospective studies to evaluate the predictive performance of cfDNA and CXCL10 prior to lung allograft failure

Broncho-alveolar lavage fluid recovery correlates with airway neutrophilia in lung transplant patients

SummaryBroncho-alveolar lavage (BAL) is important to assess airway inflammation. There is debate about the volume instilled, but the variation of BAL fluid recovery (BFR) has received little attention. We investigated the association between BFR and rejection/infection status after lung transplantation (LTx).We combined clinical findings, FEV1, transbronchial biopsies and BAL analysis (BFR, interleukin-8 (IL8), cell counts, microbiology) of 115 samples/LTx patients. The patients were divided into 4 groups: stable (subdivided in colonized and non-colonized), acute rejection (AR), Bronchiolitis Obliterans Syndrome (BOS) and infection.BFR was significantly lower in AR, BOS and infection, and correlated with the severity of AR and BOS. A 10ml decrease of BFR was associated with a FEV1 decrease of 4.4% and a %neutrophils and IL8 increase of 9.6% and 9.7pg/ml, respectively. Colonized stable patients had no significant differences in airway inflammation, FEV1 and BFR compared to the non-colonized stable patients.We conclude that a low BFR is an indicator of lung rejection or infection. BFR variation is related to airway obstruction and neutrophilic inflammation, which can cause an increased compliance of the airway wall, making it more collapsible. Airway colonization in stable patients had no effect on airway inflammatory parameters, BFR and FEV1

Pathology of Idiopathic Pulmonary Fibrosis Assessed by a Combination of Microcomputed Tomography, Histology, and Immunohistochemistry

Idiopathic pulmonary fibrosis (IPF) is a fibrotic disease showing the histology of usual interstitial pneumonia (UIP). While the pathologist's visual inspection is central in histological assessments, three-dimensional microCT assessment may complement pathologist's scoring. This study examined associations between the histopathological features of UIP/IPF in explanted lungs and quantitative microCT measurements including alveolar surface density, total lung volume taken up by tissue (tissue%), and terminal bronchiolar number. Sixty frozen samples from 10 air-inflated explanted lungs with severe IPF and 36 samples from 6 donor control lungs were scanned with microCT and processed for histology. An experienced pathologist scored 3 major UIP criteria (patchy fibrosis, honeycomb, and fibroblastic foci), 5 additional pathological changes such as emphysema, and immunohistochemical staining for CD68, CD4, CD8, and CD79a positive cells, graded on a 0-3+ scale. The alveolar surface density and terminal bronchiolar number decreased and the tissue% increased in IPF compared to controls. In lungs with IPF, lower alveolar surface density and higher tissue% were correlated with greater scores of patchy fibrosis, fibroblastic foci, honeycomb, CD79a-positive cells, and lymphoid follicles. A decreased number of terminal bronchioles was correlated with honeycomb score, but not with the other scores. The three-dimensional microCT measurements reflect the pathological UIP/IPF criteria and further suggest that the reduction in the terminal bronchioles may be associated with honeycomb cyst formation

MiR-223 is increased in lungs of patients with COPD and modulates cigarette smoke-induced pulmonary inflammation

Since microRNA (miR)-223-3p modulates inflammatory responses and chronic obstructive pulmonary disease (COPD) is associated with amplified pulmonary inflammation, we hypothesized that miR-223-3p plays a role in COPD pathogenesis. Expression of miR-223-3p was measured in lung tissue of two independent cohorts with patients with GOLD stage II-IV COPD, never smokers, and smokers without COPD. The functional role of miR-223-3p was studied in deficient mice and on overexpression in airway epithelial cells from COPD and controls. We observed higher miR-223-3p levels in patients with COPD stage II-IV compared with (non)-smoking controls, and levels were associated with higher neutrophil numbers in bronchial biopsies of patients with COPD. MiR-223-3p expression was also increased in lungs and bronchoalveolar lavage of cigarette smoke (CS)-exposed mice. CS-induced neutrophil and monocyte lung infiltration was stronger in miR-223-deficient mice on acute (5 days) exposure, but attenuated on subchronic (4 wk) exposure. Additionally, miR-223 deficiency attenuated acute and subchronic CS-induced lung infiltration of dendritic cells and T lymphocytes. Finally, in vitro overexpression of miR-223-3p in non-COPD airway epithelial cells suppressed C-X-C motif chemokine ligand 8 (CXCL8) and granulocyte monocyte-colony stimulation factor (GM-CSF) secretion and gene expression of the proinflammatory transcription factor TRAF6. Importantly, this suppressive effect of miR-223-3p was compromised in COPD-derived cultures. In conclusion, we demonstrate that miR-223-3p is increased in lungs of patients with COPD and CS-exposed mice and is associated with neutrophilic inflammation. In vivo data indicate that miR-223 acts as negative regulator of acute CS-induced neutrophilic and monocytic inflammation. In vitro data suggest that miR-223-3p does so by suppressing proinflammatory airway epithelial responses, which is less effective in COPD epithelium

A Comprehensive Review on the Surgical Aspect of Lung Transplant Models in Mice and Rats

Lung transplantation improves the outcome and quality of life of patients with end-stage pulmonary disease. However, the procedure is still hampered by the lack of suitable donors, the complexity of the surgery, and the risk of developing chronic lung allograft dysfunction. Over the past decades, translational experiments in animal models have led to a better understanding of physiology and immunopathology following the lung transplant procedure. Small animal models (e.g., rats and mice) are mostly used in experiments regarding immunology and pathobiology and are preferred over large animal models due to the ethical aspects, the cost-benefit balance, and the high throughput possibility. In this comprehensive review, we summarize the reported surgical techniques for lung transplantation in rodent models and the management of perioperative complications. Furthermore, we propose a guide to help identify the appropriate species for a given experiment and discuss recent experimental findings in small animal lung transplant models

The Role of a Panel of Pro-Fibrogenic miRs in Fibrotic Lung Disorders

Rationale: Pulmonary idiopathic fibrosis (IPF), Cryptogenetic organizing pneumonia (COP) and bronchiolitis obliterans syndrome (BOS) are rare pulmonary disorders, linked by the presence of fibrotic lesions. In our previous work (Di Carlo, 2016) on BOS we computationally identified a panel of candidate miRNAs and demonstrated by in situ hybridization analysis (ISH) and qRT-PCR, a dysregulation of two highly ranked miRNAs, miR-21 and miR-34a;ISH confirmed abnormal miR-21 and miR-34a expression in BOS lesions; other miRNAs where indicated as potential candidates in BOS by computational analysis. Aim We extended our previous work by analyzing the expression of miR-21, miR-34a and three other highly ranked miRNAs (miR-145, miR-146b-5p and miR-381) in BOS and other lung diseases associated with fibroblast activation/proliferation and collagen deposition. Identifying a specific profile of dysregulated miRNAs could provide useful diagnostic markers and potential therapeutic target. Methods :We evaluated miRNAs expression profile by ISH and RT-PCR quantification in a series of formalin-fixed and paraffin-embedded lung samples obtained from patients with IPF (n. 8), OP (n. 8), BOS (n. 12) and normal lung from organ donors. Results In BOS, COP and IPF/UIP miR-21 and miR-145 were expressed in fibroblasts of BO lesions, OP plugs and in fibroblast foci respectively, and in reactive alveolar epithelia; miR-146b expression correlated to the amount of inflammatory cell infiltrates and epithelial activation in all cases, while a weak expression was evident in OP and IPF/UIP lesions. miR-34a overexpression was associated with the activation of alveolar epithelia and to a lesser extent with fibroblast lesions in OP. miR-381 showed a weak expression in all diseases, and was localized especially in inflammatory cells. ISH data have been confirmed by qRTPCR analysis obtained on same samples. Conclusions: miR-21, miR-145 and miR-146b are over-expressed in fibroblasts in all the cases analyzed, but their expression is not disease-specific, although some differences are observed in different diseases. This finding underlies their role in non-specific fibrotic lung processes.ISH complements the results of qPCR, allows the precise cellular localization of miR expression, and improves correlations with cell-specific pathway

Thin-section Computed Tomography findings before and after azithromycin treatment of neutrophilic reversible lung allograft dysfunction

Recently a novel subgroup of bronchiolitis obliterans syndrome (BOS) has been described in patients after lung transplantation with high neutrophil counts in broncho-alveolar lavage and recovery of lung functional decline with azithromycin treatment. We aimed to describe the thin-section computed tomography (CT) findings of these neutrophilic reversible allograft dysfunction (NRAD) patients before and after azithromycin.status: publishe

Myeloid-Derived Suppressor Cells in Lung Transplantation

Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of immune cells from the myeloid lineage. MDSCs expand in pathological situations, such as chronic infection, cancer, autoimmunity, and allograft rejection. As chronic lung allograft dysfunction (CLAD) limits long-term survival after lung transplantation (LTx), MDSCs may play a role in its pathophysiology. We assessed phenotype and frequency of MDSCs in peripheral blood from lung transplant recipients and its relationship to post-transplant complications and immunosuppression. Granulocytic (G)-MDSC were identified and quantified by flow cytometry of blood from 4 control subjects and 20 lung transplant patients (stable n = 6, infection n = 5; CLAD n = 9). G-MDSC functionality was assessed in vitro by their capability to block CD4 and CD8 T cell proliferation. More G-MDSC could be assessed using EDTA tubes compared to heparin tubes (p = 0.004). G-MDSC were increased in stable lung transplant recipients vs. non-transplant controls (52.1% vs. 9.4%; p = 0.0095). The infection or CLAD groups had lower G-MDSCs vs. stable recipients (28.2%p = 0.041 and 33.0%; p = 0.088, respectively), but were not different among CLAD phenotypes. G-MDSC tended to correlate with cyclosporine A and tacrolimus levels (r2 = 0.18; r2 = 0.17). CD4 and CD8 cells proliferation decreased by 50 and 80% if co-cultured with MDSCs (1:6 and 1:2 MDSC:T-cell ratio, respectively). In conclusion, circulating MDSCs are measurable, functional and have a G-MDSC phenotype in lung transplant patients. Their frequency is increased in stable patients, decreased during post-transplant complications, and related to level of immunosuppression. This study may pave the way for further investigations of MDSC in the context of lung transplantation