Epithelial-Mesenchymal-Transition : a proposed mechanism in the development of Bronchiolitis Obliterans

La transplantation pulmonaire pour les patients avec une maladie pulmonaire en phase terminale est leur seul espoir de survie. Malheureusement, certains greffés du poumon rencontrent des difficultés après la transplantation du poumon, dont l'un est le rejet chronique du greffon pulmonaire également connu histologiquement comme la bronchiolite oblitérante et cliniquement comme syndrome de bronchiolite oblitérante. L'étiologie exacte de la BO reste mal comprise. Certaines hypothèses suggèrent l'implication des cellules épithéliales dans le processus de remodelage des voies respiratoires, conduisant à l'obstruction des voies aériennes. Un des mécanismes proposés est un processus de transition, connue sous le nom de transition épithéliale-mésenchymateuse (TEM). Lors de ce processus, les cellules perdent leurs propriétés épithéliales, acquièrent un phénotype mésenchymateux et deviennent plus mobiles et envahissantes. Cette transformation leur permet de participer activement au processus de remodelage bronchique dans la bronchiolite oblitérante. L’induction de la TEM peut être due à certains facteurs tels que l'inflammation et l'apoptose. Le principal objectif de ce travail de maîtrise est de détecter in vivo la présence de la TEM dans des biopsies transbronchiques obtenues chez des greffés et de l’associer à leurs conditions cliniques. Le deuxième objectif est d'induire la TEM in vitro dans les cellules épithéliales des petites voies aériennes à l'aide de milieux conditionnés apoptotiques et non apoptotiques produits par les cellules endothéliales microvasculaires humaines du poumon. D’autre part, nous avons évalué si des médiateurs connus pour participer au processus de TEM tels que le facteur de croissance du tissu conjonctif (CTGF)et le facteur de croissance transformant bêta (TGF-beta) ainsi que le perlecan sont présents dans les milieux conditionnés utilisés.

Activation of monocytes and cytokine production in patients with peripheral atherosclerosis obliterans

Background: Arterial peripheral disease is a condition caused by the blocked blood flow resulting from arterial cholesterol deposits within the arms, legs and aorta. Studies have shown that macrophages in atherosclerotic plaque are highly activated, which makes these cells important antigen-presenting cells that develop a specific immune response, in which LDLox is the inducing antigen. As functional changes of cells which participate in the atherogenesis process may occur in the peripheral blood, the objectives of the present study were to evaluate plasma levels of anti-inflammatory and inflammatory cytokines including TNF-alpha, IFN-gamma, interleukin-6 (IL-6), IL-10 and TGF-beta in patients with peripheral arteriosclerosis obliterans, to assess the monocyte activation level in peripheral blood through the ability of these cells to release hydrogen peroxide (H(2)O(2)) and to develop fungicidal activity against Candida albicans (C. albicans) in vitro.Methods: TNF-alpha, IFN-gamma, IL-6, IL-10 and TGF-beta from plasma of patients were detected by ELISA. Monocyte cultures activated in vitro with TNF-alpha and IFN-gamma were evaluated by fungicidal activity against C. albicans by culture plating and Colony Forming Unit (CFU) recovery, and by H(2)O(2) production.Results: Plasma levels of all cytokines were significantly higher in patients compared to those detected in control subjects. Control group monocytes did not release substantial levels of H(2)O(2) in vitro, but these levels were significantly increased after activation with IFN-gamma and TNF-alpha. Monocytes of patients, before and after activation, responded less than those of control subjects. Similar results were found when fungicidal activity was evaluated. The results seen in patients were always significantly smaller than among control subjects. Conclusions: The results revealed an unresponsiveness of patient monocytes in vitro probably due to the high activation process occurring in vivo as corroborated by high plasma cytokine levels.

Imbalanced matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 activities in patients with thromboangiitis obliterans

The pathogenic mechanisms of thromboangiitis obliterans (TAO) are not entirely known and the imbalance of matrix metalloproteinases (MMPs) plays a role in vascular diseases. We evaluated the MMP-2 and MMP-9 circulating levels and their endogenous tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in TAO patients with clinical manifestations. The study included 20 TAO patients (n = 10 female, n = 10 male) aged 38-59 years under clinical follow-up. The patients were classified into two groups: (1) TAO former smokers (n = 11) and (2) TAO active smokers (n = 9); the control group included normal volunteer non-smokers (n = 10) and active smokers without peripheral artery disease (n = 10). Patient plasma samples were used to analyze MMP-2 and MMP-9 levels using zymography, and TIMP-1 and TIMP-2 concentrations were determined by enzyme-linked immunosorbent assays. The analysis of MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios (which were used as indices of net MMP-2 and MMP-9 activity, respectively) showed significantly higher MMP-9/TIMP-1 ratios in TAO patients (p < 0.05). We found no significant differences in MMP-2/TIMP-2 ratios (p > 0.05). We found higher MMP-9 levels and decreased levels of TIMP-1 in the TAO groups (active smokers and former smokers), especially in active smokers compared with the other groups (all p < 0.05). MMP-2 and TIMP-2 were not significantly different in patients with TAO as compared to the control group (p > 0.05). In conclusion, our results showed increased MMP-9 and reduced TIMP-1 activity in TAO patients, especially in active smokers compared with non-TAO patients. These data suggest that smoke compounds could activate MMP-9 production or inhibit TIMP-1 activity.

Activation of cytokines corroborate with development of inflammation and autoimmunity in thromboangiitis obliterans patients

Thromboangiitis obliterans (TAO) is a segmental inflammatory occlusive disorder that affects the arm and leg arteries of young smokers. The immune system seems to play a critical role in the aetiology of TAO; however, knowledge of the aspects involved in the progression of vascular tissue inflammation and, consequently, the evolution of this disease is still limited. This study was carried out to investigate the cytokine levels of tumour necrosis factor (TNF)-a, interleukin (IL)-1 beta, IL-4, IL-17 and IL-23 in the plasma of TAO patients presenting with acute clinical manifestations. The study included 20 TAO patients (n = 10 women; n = 10 men) aged 3859 years under clinical follow-up, classified into two groups: (i) TAO former smokers (n = 11) and (ii) TAO active smokers (n = 9); the control groups included normal volunteer non-smokers (n = 10, active smokers (n = 10) and former smokers (n = 10). Patients' plasma samples were measured using the sandwich enzyme-linked immunosorbent assay. Statistical analyses were performed using the non-parametric MannWhitney U-test, with parameters significant at P < 0.05. The activities of all cytokines were different in groups of TAO patients when compared with normal controls, and decreased for control smokers. Increased levels of TNF-a, IL-1 beta, IL-4, IL-17 and IL-23 were significant in patients with TAO when compared to the controls (P < 0.005, all parameters). The results presented here indicate an increased production of cytokines in TAO, possibly contributing to the inflammatory response observed in the patients' vascular levels. In addition, the increased levels of IL-17 and IL-23 suggest that the disturbance of TAO is involved with mechanisms of autoimmunity. Thus, the discovery of IL-17 and its association with inflammation and autoimmune pathology has reshaped our viewpoint regarding the pathogenesis of TAO, which was based previously on the T helper type 1 (Th1)Th2 paradigm.

Oxygen-sensitive 3He-MRI in bronchiolitis obliterans after lung transplantation

Oxygen-sensitive 3He-MRI was studied for the detection of differences in intrapulmonary oxygen partial pressure (pO2) between patients with normal lung transplants and those with bronchiolitis obliterans syndrome (BOS). Using software developed in-house, oxygen-sensitive 3He-MRI datasets from patients with normal lung grafts (n = 8) and with BOS (n = 6) were evaluated quantitatively. Datasets were acqiured on a 1.5-T system using a spoiled gradient echo pulse sequence. Underlying diseases were pulmonary emphysema (n = 10 datasets) and fibrosis (n = 4). BOS status was verified by pulmonary function tests. Additionally, 3He-MRI was assessed blindedly for ventilation defects. Median intrapulmonary pO2 in patients with normal lung grafts was 146 mbar compared with 108 mbar in patients with BOS. Homogeneity of pO2 distribution was greater in normal grafts (standard deviation pO2 34 versus 43 mbar). Median oxygen decrease rate during breath hold was higher in unaffected patients (-1.75 mbar/s versus -0.38 mbar/s). Normal grafts showed fewer ventilation defects (5% versus 28%, medians). Oxygen-sensitive 3He-MRI appears capable of demonstrating differences of intrapulmonary pO2 between normal lung grafts and grafts affected by BOS. Oxygen-sensitive 3He-MRI may add helpful regional information to other diagnostic techniques for the assessment and follow-up of lung transplant recipients.

Long-term health-related quality of life and walking capacity of lung recipients with and without bronchiolitis obliterans syndrome

BACKGROUND: Outcome after lung transplantation (LTx) is affected by the onset of bronchiolitis obliterans syndrome (BOS) and lung function decline. Reduced health-related quality of life (HRQL) and physical mobility have been shown in patients developing BOS, but the impact on the capacity to walk is unknown. We aimed to compare the long-term HRQL and 6-minute walk test (6MWT) between lung recipients affected or not by BOS Grade > or =2. METHODS: Fifty-eight patients were prospectively followed for 5.6 +/- 2.9 years after LTx. Assessments included the St George's Respiratory Questionnaire (SGRQ) and the 6MWT, which were performed yearly. Moreover, clinical complications were recorded to estimate the proportion of the follow-up time lived without clinical intercurrences after transplant. Analyses were performed using adjusted linear regression and repeated-measures analysis of variance. RESULTS: BOS was a significant predictor of lower SGRQ scores (p < 0.01) and reduced time free of clinical complications (p = 0.001), but not of 6MWT distance (p = 0.12). At 7 years post-transplant, results were: 69.0 +/- 21.8% vs 86.9 +/- 5.6%, p < 0.05 (SGRQ); 58.5 +/- 21.6% vs 88.7 +/- 11.4%, p < 0.01 (proportion of time lived without clinical complications); and 82.2 +/- 10.9% vs 91.9 +/- 14.2%, p = 0.27 (percent of predicted 6MWT), respectively, for patients with BOS and without BOS. CONCLUSIONS: Despite significantly less time lived without clinical complications and progressive decline of self-reported health status, the capacity to walk of patients affected by BOS remained relatively stable over time. These findings may indicate that the development of moderate to severe BOS does not prevent lung recipients from walking independently and pursuing an autonomous life.

Airway basal stem cells: a perspective on their roles in epithelial homeostasis and remodeling.

The small airways of the human lung undergo pathological changes in pulmonary disorders, such as chronic obstructive pulmonary disease (COPD), asthma, bronchiolitis obliterans and cystic fibrosis. These clinical problems impose huge personal and societal healthcare burdens. The changes, termed 'pathological airway remodeling', affect the epithelium, the underlying mesenchyme and the reciprocal trophic interactions that occur between these tissues. Most of the normal human airway is lined by a pseudostratified epithelium of ciliated cells, secretory cells and 6-30% basal cells, the proportion of which varies along the proximal-distal axis. Epithelial abnormalities range from hypoplasia (failure to differentiate) to basal- and goblet-cell hyperplasia, squamous- and goblet-cell metaplasia, dysplasia and malignant transformation. Mesenchymal alterations include thickening of the basal lamina, smooth muscle hyperplasia, fibrosis and inflammatory cell accumulation. Paradoxically, given the prevalence and importance of airway remodeling in lung disease, its etiology is poorly understood. This is due, in part, to a lack of basic knowledge of the mechanisms that regulate the differentiation, maintenance and repair of the airway epithelium. Specifically, little is known about the proliferation and differentiation of basal cells, a multipotent stem cell population of the pseudostratified airway epithelium. This Perspective summarizes what we know, and what we need to know, about airway basal cells to evaluate their contributions to normal and abnormal airway remodeling. We contend that exploiting well-described model systems using both human airway epithelial cells and the pseudostratified epithelium of the genetically tractable mouse trachea will enable crucial discoveries regarding the pathogenesis of airway disease.

Ten years of lung transplantation in Switzerland: results of the Swiss Lung Transplant Registry.

Lung transplantation has evolved from an experimental procedure to a viable therapeutic option in many countries. In Switzerland, the first lung transplant was performed in November 1992, more than ten years after the first successful procedure world-wide. Thenceforward, a prospective national lung transplant registry was established, principally to enable quality control. The data of all patients transplanted in the two Swiss Lung Transplant centres Zurich University Hospital and Centre de Romandie (Geneva-Lausanne) were analysed. In 10 years 242 lung transplants have been performed. Underlying lung diseases were cystic fibrosis including bronchiectasis (32%), emphysema (32%), parenchymal disorders (19%), pulmonary hypertension (11%) and lymphangioleiomyomatosis (3%). There were only 3% redo procedures. The 1, 5 and 9 year survival rates were 77% (95% CI 72-82), 64% (95% CI 57-71) and 56% (95% CI 45-67), respectively. The 5 year survival rate of patients transplanted since 1998 was 72% (95% CI 64-80). Multivariate Cox regression analysis revealed that survival was significantly better in this group compared to those transplanted before 1998 (HR 0.44, 0.26-0.75). Patients aged 60 years and older (HR 5.67, 95% CI 2.50-12.89) and those with pulmonary hypertension (HR 2.01, 95% CI 1.10-3.65) had a significantly worse prognosis The most frequent causes of death were infections (29%), bronchiolitis obliterans syndrome (25%) and multiple organ failure (14%). The 10-year Swiss experience of lung transplantation compares favourably with the international data. The best results are obtained in cystic fibrosis, pulmonary emphysema and parenchymal disorders.

Rôle des eicosanoïdes post-greffe : implication dans la bronchiolite oblitérante

Le rejet chronique se manifeste dans le poumon par la bronchiolite oblitérante (BO), une pathologie inflammatoire et fibrotique menant à l’oblitération des bronchioles. L’étiologie exacte de cette maladie demeure inconnue. Certaines études suggèrent qu'un déséquilibre des leucotriènes (LT) sur les prostaglandines (PG) favorise la fibrose pulmonaire. Les taux des LT et des PG dans le poumon humain post-transplantation sont inconnus. Nous proposons qu'un déséquilibre de cystéinyl leucotriènes (CysLT) sur la PGE2 existe dans le poumon transplanté et pourrait être impliqué dans la pathogenèse de la BO. Aussi, les leucotriènes contribueraient à la fibrose par la transition épithélio-mésenchymateuse (TEM). Afin de vérifier ces hypothèses, nous avons déterminé les taux de CysLT et de PGE2 dans le liquide de lavage broncho-alvéolaire (LBA) provenant de poumons transplantés chez l'homme ainsi que leurs corrélations cliniques. Nous avons également déterminé la capacité des CysLT à induire l’expression des marqueurs de la TEM in vitro. Nous avons découvert des taux de CysLT et PGE2 supérieurs à la normale dans les LBA des greffés. Un pic prédominant de CysLT sur PGE2 est observée à 52 semaines postgreffe et deux facteurs de risque de la BO, les infections au CMV et à l’Aspergillus, sont associés au ratio CysLT/PGE2> 1. In vitro, les CysLT induisent une répression des marqueurs épithéliaux mais n’induisent pas l’expression de marqueurs mésenchymateux chez les cellules épithéliales bronchiolaires.

Hallazgos radiológicos de la enfermedad pulmonar en pacientes Colombianos con esclerodermia

La esclerosis sistémica (ES) es una enfermedad autoinmune multisistémica que afecta principalmente la piel, los pulmones, el tracto gastrointestinal, el corazón y los riñones. La enfermedad pulmonar, presente en casi el 100% de los casos, es el factor con mayor influencia en la mortalidad. El propósito de este estudio es realizar un análisis detallado de la enfermedad pulmonar por tomografía computarizada de alta resolución(TCAR) en pacientes Colombianos con ES, para lo cual se realizó un estudio de prevalencia analítica en 44 pacientes con ES valorados en el Hospital Universitario Mayor Méderi en los últimos 7 años. Los resultados mostraron características demográficas y clínicas similares a las previamente descritas. La prevalencia de enfermedad pulmonar intersticial fue alta, y los hallazgos de fibrosis pulmonar como vidrio esmerilado y panal de abejas se asociaron con la presencia del autoanticuerpo antiSCL70. La medida del diámetro esofágico por TCAR fue mayor en los pacientes con disfagia, antiSCL 70 y linfopenia, los cuales son marcadores de mal pronóstico.

BLOQUEIO PERIDURAL E TERMOMETRIA CUTANEA COMO CRITERIO PARA INDICACAO CIRURGICA DE SIMPATECTOMIA LOMBAR

To find a valuable tool in achieving a good accuracy in predicting the outcome from sympathectomy, changes in limb skin temperatures (LST) before and after epidural lumbar anesthesia (ELA) and before and after lumbar sympathectomy were studied in 13 patients with thrombangiitis obliterans or arteriosclerosis obliterans. The results were compared with the clinical course and follow-up from 1 to 5 years. In seven patients there was a rise in LST after ELA and after sympathectomy, and this pattern of variation was associated with good clinical course. In three patients there was decrease in the LST after ELA and after sympathectomy and they did not do well. In two patients there was no change in temperature before or after the procedure; one of them had a good and the other a bad clinical course. The same measurements were performed in three other patients who had had a sympathectomy some years previously and the data showed that LST was lowered after ELA. It is concluded that the measurement of limb skin temperature before and after epidural lumbar anesthesia aids in determining which patients are more likely to benefit from sympathectomy.

Chronic reparative changes in medium-sized vessels in a case of primary cutaneous anaplastic large-cell lymphoma with angioinvasive features and cytotoxic phenotype: new histopathological findings in line with indolent clinical behavior

Angioinvasion/angiodestruction has been reported in a small subset of primary cutaneous anaplastic large-cell lymphomas (PCALCL). Recently, PCALCL with angioinvasive features and cytotoxic phenotype has been characterized as a variant associated with good clinical outcomes despite worrisome histopathologic features. We report a case of PCALCL with angioinvasive features and cytotoxic phenotype associated with reparative changes on the wall of medium-sized vessels involved by the neoplasm, including intimal fibroblastic proliferation and luminal obliteration. This vascular pattern, although previously unreported in PCALCL, is in accordance with the indolent behavior observed in this entity and provides a further link with lymphomatoid papulosis type E.

Modelo experimental de perfusão pulmonar ex vivo em ratos: avaliação histopatológica e de apoptose celular em pulmões preservados com solução de baixo potássio dextrana vs. solução histidina-triptofano-cetoglutarato

OBJETIVO: Comparar os achados histopatológicos e de apoptose em pulmões de ratos preservados em soluções low-potassium dextran (LPD, baixo potássio dextrana), histidine-tryptophan-ketoglutarate (HTK, histidina-triptofano-cetoglutarato) ou salina normal (SN) em 6 h e 12 h de isquemia pela utilização de um modelo experimental de perfusão pulmonar ex vivo. MÉTODOS: Sessenta ratos Wistar foram anestesiados, randomizados e submetidos à perfusão anterógrada pela artéria pulmonar com uma das soluções preservadoras. Após a extração, os blocos cardiopulmonares foram preservados por 6 ou 12 h a 4ºC, sendo então reperfundidos com sangue homólogo em um sistema de perfusão ex vivo durante 60 min. Ao final da reperfusão, fragmentos do lobo médio foram extraídos e processados para histopatologia, sendo avaliados os seguintes parâmetros: congestão, edema alveolar, hemorragia alveolar, hemorragia, infiltrado inflamatório e infiltrado intersticial. O grau de apoptose foi avaliado pelo método TdT-mediated dUTP nick end labeling. RESULTADOS: A histopatologia demonstrou que todos os pulmões preservados com SN apresentaram edema alveolar após 12 h de isquemia. Não houve diferenças em relação ao grau de apoptose nos grupos estudados. CONCLUSÕES: No presente estudo, os achados histopatológicos e de apoptose foram semelhantes com o uso das soluções LPD e HTK, enquanto a presença de edema foi significativamente maior com o uso de SN.

Bronchoscopy for the diagnosis of pulmonary tuberculosis in patients with negative sputum smear microscopy results

Objective: To evaluate the diagnostic accuracy of bronchoscopy in patients with clinical or radiological suspicion of tuberculosis who were unable to produce sputum or with negative sputum smear microscopy results. Methods: A prospective cross-sectional study involving 286 patients under clinical or radiological suspicion of having pulmonary tuberculosis and submitted to bronchoscopy-BAL and transbronchial biopsy (TBB). The BAL specimens were submitted to direct testing and culture for AFB and fungi, whereas the TBB specimens were submitted to histopathological examination. Results: Of the 286 patients studied, 225 (79%) were diagnosed on the basis of bronchoscopic findings, as follows: pulmonary tuberculosis, in 127 (44%); nonspecific chronic inflammation, in 51 (18%); pneumocystis, fungal infections, or nocardiosis, in 20 (7%); bronchiolitis obliterans organizing pneumonia, alveolites, or pneumoconiosis, in 14 (5%); lung or metastatic neoplasms, in 7 (2%); and nontuberculous mycobacterium infections, in 6 (2%). For the diagnosis of tuberculosis, BAL showed a sensitivity and a specificity of 60% and 100%, respectively. Adding the TBB findings significantly increased this sensitivity (to 84%), as did adding the post-bronchoscopy sputum smear microscopy results (total sensitivity, 94%). Minor post-procedure complications occurred in 5.6% of the cases. Conclusions: Bronchoscopy is a reliable method for the diagnosis of pulmonary tuberculosis, with low complication rates. The combination of TBB and BAL increases the sensitivity of the method and facilitates the differential diagnosis with other diseases.

Cyclosporine A Drives a Th17‐and Th2‐Mediated Posttransplant Obliterative Airway Disease

Calcineurin-inhibitor refractory bronchiolitis obliterans (BO) represents the leading cause of late graft failure after lung transplantation. T helper (Th)2 and Th17 lymphocytes have been associated with BO development. Taking advantage of a fully allogeneic trachea transplantation model in mice, we addressed the pathogenicity of Th cells in obliterative airway disease (OAD) occurring in cyclosporine A (CsA)-treated recipients. We found that CsA prevented CD8+ T cell infiltration into the graft and downregulated the Th1 response but affected neither Th2 nor Th17 responses in vivo. In secondary mixed lymphocyte cultures, CsA dramatically decreased donor-specific IFN-γ production, enhanced IL-17 production and did not affect IL-13. As CD4+ depletion efficiently prevented OAD in CsA-treated recipients, we further explored the role of Th2 and Th17 immunity in vivo. Although IL-4 and IL-17 deficient untreated mice developed an OAD comparable to wild-type recipients, a single cytokine deficiency afforded significant protection in CsA-treated recipients. In conclusion, CsA treatment unbalances T helper alloreactivity and favors Th2 and Th17 as coexisting pathways mediating chronic rejection of heterotopic tracheal allografts.