Cathepsin C from extracellular histone-induced M1 alveolar macrophages promotes NETosis during lung ischemia-reperfusion injury.

Primary graft dysfunction (PGD) is a severe form of acute lung injury resulting from lung ischemia/reperfusion injury (I/R) in lung transplantation (LTx), associated with elevated post-transplant morbidity and mortality rates. Neutrophils infiltrating during reperfusion are identified as pivotal contributors to lung I/R injury by releasing excessive neutrophil extracellular traps (NETs) via NETosis. While alveolar macrophages (AMs) are involved in regulating neutrophil chemotaxis and infiltration, their role in NETosis during lung I/R remains inadequately elucidated. Extracellular histones constitute the main structure of NETs and can activate AMs. In this study, we confirmed the significant involvement of extracellular histone-induced M1 phenotype of AMs (M1-AMs) in driving NETosis during lung I/R. Using secretome analysis, public protein databases, and transwell co-culture models of AMs and neutrophils, we identified Cathepsin C (CTSC) derived from AMs as a major mediator in NETosis. Further elucidating the molecular mechanisms, we found that CTSC induced NETosis through a pathway dependent on NADPH oxidase-mediated production of reactive oxygen species (ROS). CTSC could significantly activate p38 MAPK, resulting in the phosphorylation of the NADPH oxidase subunit p47phox, thereby facilitating the trafficking of cytoplasmic subunits to the cell membrane and activating NADPH oxidase. Moreover, CTSC up-regulated and activated its substrate membrane proteinase 3 (mPR3), resulting in an increased release of NETosis-related inflammatory factors. Inhibiting CTSC revealed great potential in mitigating NETosis-related injury during lung I/R. These findings suggests that CTSC from AMs may be a crucial factor in mediating NETosis during lung I/R, and targeting CTSC inhition may represent a novel intervention for PGD in LTx.

Evolución clínica, funcional y radiológica de pacientes trasplantados pulmonares con síndrome de bronquiolitis obliterante y disfunción de injerto pulmonar restrictivo / Clinical, functional and radiological evolution of pulmonary transplant patients with bronchiolitis obliterans syndrome and restrictive graft dysfunction

Resumen La principal complicación a largo plazo en trasplantados de pulmón es la disfunción crónica de injerto identificado como bronquiolitis obliterante, existiendo un nuevo patrón denominado Disfunción de Injerto Restrictivo. Objetivo: Evaluar seguimiento espirométrico, radiológico y clínico entre pacientes con síndrome de bronquiolitis obliterante (SBO) y Disfunción de Injerto Restrictivo (DIR) post trasplante pulmonar. Metodología: Se revisaron registros clínicos de trasplantados pulmonares desde 1999 hasta 2017. Se efectuó seguimiento espirométrico e imágenes por tomografía de tórax y factores asociados: infección por Citomegalovirus(CMV), reflujo gastro-esofágico (RGE) y episodios de rechazo agudo. Se analizó sobrevida por Kaplan Meier. Resultados: De 88 pacientes trasplantados de pulmón, 40 desarrollaron disfunción crónica de injerto: 31 (80%) presentaron SBO y 9 (20%) tuvieron DIR. Edad promedio: 47 años en SBO y 46 años en DIR. Siendo fibrosis pulmonar la patología basal predominante en ambos. En SBO se consignaron 14 episodios de rechazo agudo (50%), infección por CMV en 18% y RGE activo en 26%. En la serie DIR hubo 5 episodios de rechazo agudo (62%), 13% de infección por CMV y 67% de RGE activo 6 (p = 0,02). En el seguimiento a 1-2-4-5 años el promedio del VEF1 en SBO fue: 67,3,65, 60 y 48% del valor predicho y en DIR fue 61, 65, 62 y 45% respectivamente. Las imágenes tomográficas en SBO mostraron: hiperinflación y en DIR: fibrosis pleuropulmonar superior. La sobrevida fue de 96,9 meses en SBO y 65,6 meses en DIR (p = 0,06). Conclusions: La disfunción restrictiva presentó menor sobrevida que SBO. RGE se asoció a rechazo restrictivo. La tomografía de tórax difiere en ambos tipos de rechazo crónico.

The main long-term complication in lung transplant patients is chronic graft dysfunction identified as bronchiolitis obliterans, and there is a new pattern called Restrictive Graft Dysfunction. Objective: To evaluate spirometric, radiological and clinical follow-up among patients with bronchiolitis obliterans syndrome (BOS) and Restrictive Allograft Syndrome (RAS) after lung transplantation. Methodology: Lung transplant recipients ' clinical records were reviewed from 1999 to 2017. We carried out a follow up of spirometry, chest tomography imaging and associated factors: cytomegalovirus (CMV) infection, gastroesophageal reflux (GER) and episodes of acute rejection. Survival was analyzed by Kaplan Meier. Results: Out of 88 lung transplant patients, 40 developed chronic graft dysfunction: 31 (80%) presented BOS and 9 (20%) had RAS. Mean age: 47 yr.o. in BOS and 46 yr. o. in RAS. Lung fibrosis was the primary pathology predominant in both conditions. In BOS were reported 14 episodes of acute rejection (50%), CMV infection in 18% and active GER in 26%. In RAS there were 5 episodes of acute rejection (62%), CMV infection in 13% and active GER in 67% (p = 0.02). VEF1 follow-up at 1-2-4-5 years averaged 67, 65, 60 and 8% of reference value in BOS and 61, 65, 62 and 45% in RAS respectively. CT scans showed hyperinflation in BOS and upper pleuropulmonary fibrosis in RAS. BOS survival time was 96.9 months versus 65.6 months in RAS (p = 0.06). Conclusiones: Restrictive dysfunction presented a lower survival rate than BOS. GER was associated with restrictive rejection. Chest tomography differs in both types of chronic rejection.

Upregulation of microRNA 142-3p in the peripheral blood and urinary cells of kidney transplant recipients with post-transplant graft dysfunction

We analyzed microRNA (miR)-142-3p expression in leucocytes of the peripheral blood and urinary sediment cell samples obtained from kidney transplant recipients who developed graft dysfunction. Forty-one kidney transplant recipients with kidney graft dysfunction and 8 stable patients were included in the study. The groups were divided according to histological analysis into acute rejection group (n=23), acute tubular necrosis group (n=18) and stable patients group used as a control for gene expression (n=8). Percutaneous biopsies were performed and peripheral blood samples and urine samples were obtained. miR-142-3p was analyzed by real-time polymerase chain reaction. The group of patients with acute tubular necrosis presented significantly higher expressions in peripheral blood (P<0.05) and urine (P<0.001) compared to the stable patients group. Also, in the peripheral blood, miR-142-3p expression was significantly higher in the acute tubular necrosis group compared to the acute rejection group (P<0.05). Urine samples of the acute rejection group presented higher expression compared to the stable patients group (P<0.001) but the difference between acute tubular necrosis and acute rejection groups was not significant in the urinary analyzes (P=0.079). miR-142-3p expression has a distinct pattern of expression in the setting of post-operative acute tubular necrosis after kidney transplantation and may potentially be used as a non-invasive biomarker for renal graft dysfunction.

The role of bradykinin in lung ischemia-reperfusion injury in a rat lung transplantation model

ABSTRACT PURPOSE: To investigate the role of bradykinin in a rat lung transplantation (LTx) model and preliminarily discuss the relationship between bradykinin and CD26/DPP-4. METHODS: Rats were randomly divided into four groups: Control (CON), Sham, low potassium dextranglucose (LPD), and AB192 (n=15/group). Orthotopic single LTx was performed in the LPD and AB192 groups. The donor lungs were flush-perfused and preserved with low potassium dextranglucose (LPD) or LPD+CD26/DPP-4 catalytic inhibitor (AB192). LTx was performed after 18 h cold ischemia time and harvested two days post-LTx. Blood gas analysis (PO2), wet/dry weight ratio (W/D), myeloperoxidase activity (MPO), and lipid peroxidation (MDA) were analyzed at 48 hr after transplantation. Immunohistochemical (IHC) analysis was performed in the same sample and validated by Western-Blot. RESULTS: Compared to the LPD group, the AB192 group showed higher PO2, lower W/D ratio, and decreased MPO and MDA. IHC studies showed strong bradykinin β2 receptor (B2R) staining in the LPD group, especially in inflammatory cells, alveolar macrophages, and respiratory epithelial cells. Expression of B2R by Western-Blot was significantly different between the AB192 and LPD groups. CONCLUSION: Bradykinin may be a competitive substrate of DPP-4, and decreased bradykinin levels may enhance protective effects against ischemia/reperfusion injury during LTx.

Bone Marrow-derived Mesenchymal Stem Cells and Chronic Allograft Disease in a Bronchiolitis Obliterans Animal Model / Células mesenquimales derivadas de médula ósea y disfunción crónica del injerto en un modelo animal de bronquiolitis obliterante

INTRODUCTION: Bronchiolitis obliterans (BO) is the most common expression of chronic allograft dysfunction in lung transplantation. Moreover, BO represents the major cause of death in the long-term after this procedure. On the other hand, mesenchymal stem cells have been tested in animal models of BO aiming to interfere in its development. The aim of this experimental study is to explore the role of bone-marrow derived stem cells (BMSCs) as a preventive intervention of BO occurrence. MATERIALS AND METHODS: This an experimental randomized study. A bronchiolitis obliterans animal model in rats was reproduced: heterotopical tracheal transplant model in lung parenchyma. Five of these animals were used as control group. After setting up the model, individuals were divided in 3 groups of treatment (n = 15), in which BMSCs were administered in 3 different time points after the tracheal transplant (tracheal transplantation and BMSCs administration occurred the same day, group G0; after 7 days, group G7; after 14 days, group G14. In addition, within each group, BMSCs were administered through 3 different routes: endotracheally, endovascular and topically in the lung parenchyma). Animals were sacrificed at 21 days. Histology, fluorescence in situ hybridization and immunohistochemistry techniques were performed for identifying stem cells. RESULTS: Compared to control group, animals receiving BMSCs showed large neovessels in a loose fibrous matrix. Group G7 showed less fibrosis (p < 0.033) and edema (p < 0.028). Moreover, G7 animals receiving stem cells endotracheally showed no fibrosis (p < 0.008). Alveolar-like patches of tissue were observed among all groups (53.4%, 46.7% and 40% in G0, G7 and G14 respectively), consisting of cells expressing both stem and alveolar cells biomarkers. CONCLUSION: BMSCs modify the course of bronchiolitis obliterans and differentiate into alveolar cells. Endotracheal administration of BMSCs 7 days after the heterotopical tracheal transplant might be considered an effective way to prevent BO in this animal model

INTRODUCCIÓN: La bronquiolitis obliterante (OB) es la forma más frecuente de disfunción crónica del injerto en el trasplante pulmonar. Asimismo, representa la principal causa de mortalidad a largo plazo tras este procedimiento. Por otro lado, las células madre mesenquimales se han utilizado en diferentes modelos animales de BO, con el propósito de interferir en el desarrollo de dicha disfunción. El objetivo de este estudio experimental es explorar el papel del trasplante de células madre mesenquimales derivadas de la médula ósea (BMSC, por sus siglas en inglés) como tratamiento preventivo de la BO. MATERIAL Y MÉTODOS: Se trata de un estudio experimental y aleatorizado en el que se empleó un modelo de BO en ratas basado en el trasplante traqueal heterotópico en parénquima pulmonar. Los animales se dividieron en los siguientes grupos: grupo control (n = 5) y 3 grupos de tratamiento (n = 15) en los que las células madre mesenquimales derivadas de médula ósea se administraron a distintos tiempos tras el trasplante traqueal heterotópico (el mismo día [grupo G0]; a 7 días [grupo G7], y a 14 días [grupo G14]). Además, dentro de cada grupo, las células se trasplantaron mediante 3 vías diferentes: endotraqueal, endovascular y tópicamente en el parénquima pulmonar. Todos los animales se sacrificaron a los 21 días tras el trasplante traqueal. Las células madre se identificaron mediante técnicas histológicas utilizando hibridación fluorescente in situ (FISH) e inmunohistoquímica. RESULTADOS: Comparado con el grupo control, los animales que recibieron las BMSC mostraron neovasos de gran tamaño en una matriz muy laxa de tejido fibroso. En el grupo G7 se observó menor grado de fibrosis (p < 0,033) y edema (p < 0,028). Además, ninguno de los animales del grupo G7 que recibieron las células madre por vía endotraqueal desarrolló algún grado de fibrosis (p < 0,008). En todos los grupos se observaron parches de tejido con características histológicas similares al tejido alveolar (53,4, 46,7% y 40% in G0, G7 y G14, respectivamente) con expresión de marcadores tanto alveolares como de células madre. CONCLUSIONES: Las células madre mesenquimales derivadas de la médula ósea modifican el curso histopatológico de la BO y son capaces de diferenciarse a células de tipo alveolar. La administración endotraqueal de estas células a los 7 días del trasplante traqueal heterotópico podría considerarse una vía efectiva para prevenir el desarrollo de BO en este modelo animal

Transforming growth factor-β in graft vessels: histology and immunohistochemistry

OBJECTIVES: The biological functions of transforming growth factor-β signaling that involves Smad proteins have not been previously investigated with respect to coronary artery bypass grafts. The aim of the present study was to observe the immunostaining of proteins that are related to this signaling pathway. METHODS: Fifteen remnants of coronary artery bypass grafts, including nine saphenous veins, three radial arteries and three mammary arteries, were collected from 12 patients who were undergoing coronary artery bypass. Hematoxylin and eosin, Masson's trichrome, and immunohistochemical staining of transforming growth factor-β1, type I receptor of transforming growth factor-β, Smad2/3, Smad4, and Smad7 were performed. RESULTS: The saphenous veins showed more severe intimal degeneration, more severe smooth muscle cell proliferation and more collagen deposition than the arterial grafts, as evidenced by hematoxylin and eosin and Masson's trichrome stainings. Immunohistochemical assays demonstrated that the majority of the transforming growth factor-β1 signaling cytokines were primarily localized in the cytoplasm in the medial layers of all three types of grafts, whereas ectopic transforming growth factor-β1, type I receptor of transforming growth factor-β, and Smad7 overexpressions in the interstices were observed particularly in the saphenous vein and radial arterial grafts. CONCLUSION: Enhanced transforming growth factor-β1 signal transduction with medial smooth muscle cell proliferation and ectopic transforming growth factor-β1, the presence of the type I receptor of transforming growth factor-β, and Smad7 overexpressions in the extracellular matrix may provide primary evidence for early or late graft failure.