Visualization of respiratory flows from 3D reconstructed alveolar airspaces using X-ray tomographic microscopy

A deeper knowledge of the three-dimensional (3D) structure of the pulmonary acinus has direct applications in studies on acinar fluid dynamics and aerosol kinematics. To date, however, acinar flow simulations have been often based on geometrical models inspired by morphometrical studies; limitations in the spatial resolution of lung imaging techniques have prevented the simulation of acinar flows using 3D reconstructions of such small structures. In the present study, we use high-resolution, synchrotron radiation-based X-ray tomographic microscopy (SRXTM) images of the pulmonary acinus of a mouse to reconstruct 3D alveolar airspaces and conduct computational fluid dynamic (CFD) simulations mimicking rhythmic breathing motion. Respiratory airflows and Lagrangian (massless) particle tracking are visualized in two examples of acinar geometries with varying size and complexity, representative of terminal sacculi including their alveoli. The present CFD simulations open the path towards future acinar flow and aerosol deposition studies in complete and anatomically realistic multi-generation acinar trees using reconstructed 3D SRXTM geometries

Evaluating Small Airways Disease in Asthma and COPD using the Forced Oscillation Technique and Magnetic Resonance Imaging

Obstructive lung disease, including asthma and chronic obstructive pulmonary disease (COPD), is characterized by heterogeneous ventilation. Unfortunately, the underlying structure-function relationships and the relationships between measurements of heterogeneity and patient quality-of-life in obstructive lung disease are not well understood. Hyperpolarized noble gas MRI is used to visualize and quantify ventilation distribution and the forced oscillation technique (FOT) applies a multi-frequency pressure oscillation at the mouth to measure respiratory impedance to airflow (including resistance and reactance). My objective was to use FOT, ventilation MRI and computational airway tree modeling to better understand ventilation heterogeneity in asthma and COPD. FOT-measured respiratory system impedance was correlated with MRI ventilation heterogeneity and both were related to quality-of-life in asthma and COPD. FOT-measurements and model-predictions of reactance and small-airways resistance were correlated in asthma and COPD respectively. This study is the first to demonstrate the relationships between FOT-measured impedance, MRI ventilation heterogeneity, and patient quality-of-life

Relaciones estructura-función en complejos surfactante pulmonar intracelulares y secretados : desarrollo e implementación de modelos celulares

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Biológicas, Departamento de Bioquímica y Biología Molecular I, leída el 14-07-2015El surfactante pulmonar (SP) es un complejo lipoproteico esencial, cuya principal función es la disminución de la tensión superficial en la interfase aire-líquido de los alvéolos, evitando su colapso al final de la espiración. El SP está constituido por un 90% de lípidos y un 10% de proteínas específicas y es producido y secretado por las células alveolares tipo II (ATII), un tipo celular especializado del epitelio alveolar. Previamente a la exocitosis del surfactante, éste es almacenado en orgánulos especiales de las células ATII denominados cuerpos lamelares (Lamellar Bodies, LBs). En la presente tesis doctoral se ha estudiado la organización estructural micro- y nanoscópica de las membranas de SP almacenadas intracelularmente como LBs en cultivos primarios de células ATII, así como recién secretadas por los mismos, en forma de LBPs (Lamellar Body-like Particles), en comparación con el surfactante nativo (SN) purificado a partir de lavados broncoalveolares de animales, un material de referencia en estudios estructurales y funcionales. Los resultados de esta tesis han revelado que las membranas de SP, tanto en forma de LBs como de LBPs, presentan propiedades estructurales y funcionales muy diferentes a las del SN. En particular, los LBs muestran un alto grado de empaquetamiento y deshidratación, que se mantiene cuando son secretados al medio extracelular en forma de LBPs, incluso a temperaturas suprafisiológicas. Asimismo, los resultados apuntan a la posible existencia en los LBPs de organizaciones distintas a las típicas de fases lamelares. Desde un punto de vista funcional, los LBPs recién secretados demuestran una superior eficiencia en términos de adsorción, así como una significativa resistencia a agentes inhibitorios, incluso a altas concentraciones de éstos, en comparación con los complejos de SN. En vista de estos resultados, se concluye que la particular complejidad interna que adoptan los lípidos y proteínas dentro de los LBPs podría conferirles propiedades críticas para una eficacia máxima en la formación de películas interfaciales y por tanto para la función surfactante. Un detallado análisis del SN ha corroborado la naturaleza heterogénea de las preparaciones purificadas a partir de lavado broncoalveolar, conteniendo no sólo estructuras activas sino también material menos eficiente y con una reducida actividad biofísica, correlacionada con una diferente ultraestructura y composición bioquímica. El material menos activo es posible que corresponda a surfactante ya ¿gastado¿ o ¿desactivado¿ o con funciones alternativas más allá de la reducción de la tensión superficial. Sin embargo, a pesar de la utilidad y fiabilidad demostradas por los cultivos primarios de células ATII, éstas tienen la desventaja de perder su fenotipo diferenciado en cultivo y son incapaces de sintetizar surfactante de novo una vez son extraídas del pulmón, lo cual impide llevar a cabo estudios sobre la biogénesis del SP. En vista de la necesidad de un modelo bien establecido de célula ATII, en esta Tesis se ha desarrollado y caracterizado un nuevo modelo celular basado en la diferenciación pulmonar de células madre humanas mesenquimales derivadas de la decidua placentaria, hasta dar lugar a unas células que hemos denominado ATII-LCs (Alveolar Type II-Like Cells). Estas células diferenciadas son capaces de expresar marcadores alveolares a nivel génico y proteico, así como sintetizar y almacenar fosfolípidos característicos del SP en orgánulos similares a LBs. Igualmente, tras estimulación fisiológica, las ATII-LCs secretan al medio extracelular complejos surfactantes con una rápida capacidad de adsorción y resistencia a inactivación. Asimismo, el modelo de ATII-LCs es sensible a la citotoxicidad de compuestos nanoestructurados de interés biofarmacéutico, constituyendo una potencial herramienta de cribado para detectar potenciales riesgos de nanofármacos en sus primeras etapas de desarrollo.Sección Deptal. de Bioquímica y Biología Molecular (Biológicas)Fac. de Ciencias BiológicasTRUEunpu

Keuhkojen rakenteen ja toiminnan kuvantaminen synkrotronisäteilyllä

A novel method for functional lung imaging was introduced by adapting the K-edge subtraction method (KES) to in vivo studies of small animals. In this method two synchrotron radiation energies, which bracket the K-edge of the contrast agent, are used for simultaneous recording of absorption-contrast images. Stable xenon gas is used as the contrast agent, and imaging is performed in projection or computed tomography (CT) mode. Subtraction of the two images yields the distribution of xenon, while removing practically all features due to other structures, and the xenon density can be calculated quantitatively. Because the images are recorded simultaneously, there are no movement artifacts in the subtraction image. Time resolution for a series of CT images is one image/s, which allows functional studies. Voxel size is 0.1mm3, which is an order better than in traditional lung imaging methods. KES imaging technique was used in studies of ventilation distribution and the effects of histamine-induced airway narrowing in healthy, mechanically ventilated, and anaesthetized rabbits. First, the effect of tidal volume on ventilation was studied, and the results show that an increase in tidal volume without an increase in minute ventilation results a proportional increase in regional ventilation. Second, spiral CT was used to quantify the airspace volumes in lungs in normal conditions and after histamine aerosol inhalation, and the results showed large patchy filling defects in peripheral lungs following histamine provocation. Third, the kinetics of proximal and distal airway response to histamine aerosol were examined, and the findings show that the distal airways react immediately to histamine and start to recover, while the reaction and the recovery in proximal airways is slower. Fourth, the fractal dimensions of lungs was studied, and it was found that the fractal dimension is higher at the apical part of the lungs compared to the basal part, indicating structural differences between apical and basal lung level. These results provide new insights to lung function and the effects of drug challenge studies. Nowadays the technique is available at synchrotron radiation facilities, but the compact synchrotron radiation sources are being developed, and in relatively near future the method may be used at hospitals.Tutkimuksen taustaa: Useimmissa keuhkosairauksissa, erityisesti astmassa ja keuhkoahtaumataudissa kaasujen vaihdunta keuhkoissa on häiriytynyt ja keuhkotuuletuksen jakauma on epätasainen. Keuhkojen tuuletuskykyä tutkitaan perinteisesti spirometrialla. Keuhkojen alueellisen toiminnan kuvantamiseen käytetään kliinisesti radionuklidimenetelmiä, joissa erotuskyky on 1-2 senttimetrin luokkaa. Käytössä olevien kuvantamismenetelmien erotuskyky ei ole riittävän tarkka kuvaamaan keuhkojen ääreisosien rakennetta ja toimintaa. Nykyiset menetelmät eivät myöskään ole täysin kvantitatiivisia. Tieto keuhkojen toiminnasta on tähän mennessä rajoittunut alueellisiin suureisiin ja tästä johtuen keuhkojen ääreisosien toiminta on huonosti tunnettu. Tässä väitöskirjatyössä on kehitetty synkrotronisäteilyn käyttöön perustuva uusi menetelmä, jonka avulla keuhkojen ääreisosien toimintaa ja rakennetta voidaan tutkia entistä tarkemmin. Tutkimusmenetelmästä: Synkrotronisäteily on hiukkaskiihdyttimessä tuotettua röntgensäteilyä, jota on perinteisesti käytetty fysiikassa materiaalitutkimuksissa. Synkrotronisäteilyn käyttö lääketieteellisissä tutkimuksissa on suhteellisen uusi tutkimusala, ja yksi menetelmistä on K-reuna vähennyskuvaus (K-edge subtraction imaging, KES). KES-kuvauksessa kuvataan varjoaineen jakautumaa kohteessa käyttäen kahta röntgensäteilyn aallonpituutta, jotka ovat eri puolilla varjoaineena käytettävän stabiilin ksenon-kaasun K-absorptioreunaa. Varjoaineen jakauma keuhkoissa voidaan kuvata CT leikekuvina tai kolmiulotteisesti spiraali-CT:llä, ja hengitystiet sekä keuhkojen ääreisosat saadaan näkyviin. Varjoaineen tiheys voidaan mitata ja sen määrä keuhkoissa on suoraan verrannollinen paikalliseen keuhkotuuletukseen. Kuvien resoluutio on 0.1mm3 ja vertailtuna muihin menetelmiin resoluutio, tarkkuus ja herkkyys tekevät KES-menetelmästä ainutlaatuisen. Tuloksista ja niiden merkityksestä: Väitöskirjatyössä menetelmää on sovellettu keuhkojen rakenteen ja toiminnan yksityiskohtaiseen tutkimiseen ja ymmärtämiseen. Menetelmää on menestyksekkäästi sovellettu keuhkotuuletuksen jakauman tutkimiseen, keuhkojen ja keuhkoputkien kolmiulotteiseen kuvantamiseen ja histamiinilla aiheutetun keuhkoputkien supistumisen dynamiikan tutkimiseen nukutetuilla kaneilla. Tulokset tuovat uutta tietoa keuhkojen toiminnasta ja astmatyyppisistä reaktioista sekä niiden vaikutuksesta keuhkotuuletukseen ja keuhkotilavuuksiin. Toistaiseksi tutkimus voidaan tehdä vain synkrotroni-tutkimuslaitoksissa, mutta kehitteillä on sairaalakäyttöön soveltuvia synkrotronilähteitä; lähitulevaisuudessa menetelmää voitaneen käyttää myös sairaalatutkimuksissa

Desafios na reclassificação anatomopatológica da malformação congênita de vias aéreas pulmonares

As malformações congênitas pulmonares (MCP) ocorrem devido ao desenvolvimento aberrante intrauterino, a partir de falhas do desenvolvimento do intestino primitivo e sua diferenciação em sistema respiratório. Dentre as doenças císticas congênitas, a malformação congênita das vias aéreas pulmonares (congenital pulmonary airway malformation – CPAM), anteriormente denominada como malformação adenomatóide cística congênita (congenital cystic adenomatoid malformation – CCAM), possui lugar de relevância clínica e epidemiológica. Apesar de representar desordem incomum, corresponde a aproximadamente 30% das malformações pulmonares congênitas. A apresentação clínica da CPAM é variada, podendo ser identificada ainda no período pré-natal a partir do exame de ultrassonografia morfológica, ou até mesmo permanecer assintomática até a idade adulta. Dentre os diagnósticos diferenciais da CPAM, encontram-se o sequestro pulmonar, a hérnia diafragmática congênita, o cisto broncogênico, o enfisema lobar congênito e o enfisema intersticial localizado, além de pneumatoceles pós-infecciosas e o blastoma pleuropulmonar. Em 1977, Stocker, propôs uma classificação em três subtipos de acordo com os achados histológicos, que foi expandida para cinco subtipos em 2002. Esta ainda é a classificação mais utilizada para as descrições anatomopatológicas da CPAM na atualidade. Nenhum estudo de revisão até o momento avaliou possíveis mudanças no diagnóstico histopatológico da doença após a revisão e reestruturação da sua classificação. Este fato, aliado à escassez de estudos na América Latina sobre o tema, justificam a realização dos trabalhos aqui expostos. Desse modo, foram realizados uma revisão das classificações da CPAM e um estudo de coorte pediátrica, com pacientes que apresentaram diagnóstico anatomopatológico de CPAM/CCAM. Foram avaliadas as características da população estudada, além da revisão das lâminas e blocos de material anatomopatológico, com vistas à reclassificação das lesões e avaliação das possíveis mudanças diagnósticas. Trinta e nove pacientes foram inicialmente incluídos, dos quais vinte e quatro tiveram material anatomopatológico revisado. Foram observadas onze alterações diagnósticas após a revisão, inclusive a descoberta de dois pacientes portadores de blastoma pleuropulmonar tipo I e Ir.Congenital pulmonary malformations (CPM) occur due to aberrant intrauterine development, caused by deficits in the development of the foregut and its differentiation in respiratory system. Among congenital cystic diseases, congenital pulmonary airway malformation (CPAM), previously called congenital cystic adenomatoid malformation (CCAM), has clinical and epidemiological relevance. Although it represents an unusual disorder, it corresponds to approximately 30% of the congenital pulmonary malformations. The clinical presentation of CPAM is diversified and can be identified even in the prenatal period from the morphological ultrasound examination or it can remain asymptomatic until adulthood. Differential diagnoses of CPAM comprise pulmonary sequestration, congenital diaphragmatic hernia, bronchogenic cyst, congenital lobar emphysema and localized interstitial emphysema, as well as postinfectious pneumatoceles and pleuropulmonary blastoma. In 1977, Stocker proposed a classification of CPAM into three subtypes according to the histological findings, which was expanded to five subtypes and in 2002. This is still the most commonly used classification for anatomopathological descriptions of CPAM today. No review studies have yet evaluated possible changes in the histopathological diagnosis of the disease, following the revised and restructured classification. This fact, allied to the scarcity of publications in Latin America about this disease, justify the accomplishment of the study presented here. Thus, we did a review of the CPAM’s classification and a pediatric cohort study was performed with patients who presented pathological diagnosis of CPAM/CCAM. The characteristics of the studied population were evaluated, as well as the revision of the slides and blocks of anatomopathological material, with the aim of the reclassification of the lesions and evaluation of possible diagnostic changes. Thirty-nine patients were initially included, of whom twenty-four had reviewed material. Eleven diagnostic alterations were observed after the review, including the discovery of two patients with pleuropulmonary blastoma type I and Ir

Diseases of the Chest, Breast, Heart and Vessels 2019-2022

This open access book focuses on diagnostic and interventional imaging of the chest, breast, heart, and vessels. It consists of a remarkable collection of contributions authored by internationally respected experts, featuring the most recent diagnostic developments and technological advances with a highly didactical approach. The chapters are disease-oriented and cover all the relevant imaging modalities, including standard radiography, CT, nuclear medicine with PET, ultrasound and magnetic resonance imaging, as well as imaging-guided interventions. As such, it presents a comprehensive review of current knowledge on imaging of the heart and chest, as well as thoracic interventions and a selection of "hot topics". The book is intended for radiologists, however, it is also of interest to clinicians in oncology, cardiology, and pulmonology

Diseases of the Chest, Breast, Heart and Vessels 2019-2022

This open access book focuses on diagnostic and interventional imaging of the chest, breast, heart, and vessels. It consists of a remarkable collection of contributions authored by internationally respected experts, featuring the most recent diagnostic developments and technological advances with a highly didactical approach. The chapters are disease-oriented and cover all the relevant imaging modalities, including standard radiography, CT, nuclear medicine with PET, ultrasound and magnetic resonance imaging, as well as imaging-guided interventions. As such, it presents a comprehensive review of current knowledge on imaging of the heart and chest, as well as thoracic interventions and a selection of "hot topics". The book is intended for radiologists, however, it is also of interest to clinicians in oncology, cardiology, and pulmonology

Post-TB lung damage amongst Malawian adults

INTRODUCTION: Pulmonary tuberculosis (PTB) remains an important risk factor for chronic lung disease (CLD) in sub-Saharan Africa (sSA), but our understanding of the nature of post-TB lung damage, its evolution over time, and the associated morbidity remains limited. This information is needed to inform clinical care and health system approaches to the management of those surviving PTB disease. METHODS: A general review of the literature on CLDs in sSA, TB disease and epidemiology, and post-TB lung damage and its associated morbidity were completed, followed by a systematic review of the prevalence and pattern of post-TB structural lung pathology. Primary data presented in this thesis were drawn from two studies based in urban Blantyre, Malawi. The first was a cross-sectional survey of respiratory abnormalities amongst adults in the community which was completed as part of the Burden of Obstructive Lung Disease (BOLD) initiative. The second was a prospective cohort study of HIV-positive and negative adults completing treatment for PTB which aimed to describe a) the prevalence of respiratory pathology at TB treatment completion using symptoms, quality of life scores, spirometry and high-resolution CT imaging, and b) the relationships between post-TB lung damage at treatment completion and adverse outcomes over 1-year of followup. RESULTS: The systematic review identified 39 studies of variable quality describing post-TB structural lung damage. A lack of prospective data, and data from sSA and HIV-positive groups was noted. Few studies related structural damage to symptoms, spirometry, or morbidity. The BOLD data estimated a high burden of respiratory symptoms and abnormal spirometry amongst adults aged ≥18 years in urban Blantyre: 11.8% reported ≥1 symptom, and 4.8% had airway obstruction. The prevalence of the low-FVC pattern of abnormal spirometry varied according to the reference range used for standardisation, from 9.0% (local reference range) to 38.6% (NHANES III reference range). A considerable burden of residual lung pathology was seen amongst 405 adults completing treatment for PTB in Blantyre: 60.7% had ongoing weekly/monthly respiratory symptoms, and 34.2% of participants had abnormal spirometry at PTB treatment completion. Participants had a median of 1.4 lobes of abnormal parenchyma on CT imaging. Moderate-severe bronchiectasis was seen in 44%, and 9.6% had ≥1 ‘destroyed’ lobe. The burden of pathology was lower in HIV-positive vs. HIV-negative adults, but patterns of abnormality were similar. The odds of ongoing respiratory symptoms or an impaired quality of life at 1-year were over three-fold higher amongst those with both extensive structural damage and abnormal spirometry at PTB treatment completion. CONCLUSION: Post-TB lung damage is a common but neglected form of CLD amongst both HIV-positive and negative adults in Malawi, and occurs against a high background prevalence of respiratory symptoms and abnormal spirometry in the community. Severe forms are associated with considerable ongoing morbidity including persistent symptoms and reduced quality of life. Further work is required to understand the range of patterns of post-TB lung damage, and their relationship with long-term outcomes such as respiratory exacerbations and mortality. However, this is a neglected population and interventions to maximise their health following PTB treatment completion are required

Current Frontiers and Perspectives in Cell Biology

A numerous internationally renowned authors in the pages of this book present the views of the fields of cell biology and their own research results or review of current knowledge. Chapters are divided into five sections that are dedicated to cell structures and functions, genetic material, regulatory mechanisms, cellular biomedicine and new methods in cell biology. Multidisciplinary and often quite versatile approach by many authors have imposed restrictions of this classification, so it is certain that many chapters could belong to the other sections of this book. The current frontiers, on the manner in which they described in the book, can be a good inspiration to many readers for further improving, and perspectives which are highlighted can be seen in many areas of fundamental biology, biomedicine, biotechnology and other applications of knowledge of cell biology. The book will be very useful for beginners to gain insight into new area, as well as experts to find new facts and expanding horizons