Background: Among the common malignancies, pancreatic cancer has the shortest long-term survival. The aggressive, rapid, and infiltrative growth pattern of pancreatic cancer, together with the lack of specific symptoms, often leads to late diagnosis. Metastases are frequently found at the time of diagnosis, which prevents curative surgical treatment. Good tumor markers would enable early detection, thus improving the prognosis. Unfortunately, no such markers are available in the clinic. The tumor stroma is defined as the non-malignant cells and the extracellular matrix (ECM) of a cancer. Pancreatic cancer is characterized by an abundant tumor stroma, rich in ECM proteins such as collagens, which have been shown to play important roles in tumor progression. Furthermore, pancreatic cancer cells produce large quantities of ECM proteins, especially the basement membrane (BM) protein type IV collagen. All epithelial cells are anchored to a BM, which must be degraded in order for an in situ cancer to become invasive. Matrix metalloproteinases (MMPs) are enzymes involved in BM degradation. In this thesis, the tumor stroma of pancreatic cancer is studied, focusing on the BM proteins type IV and type XVIII collagen, with the aim to clarify if the stroma could be a source of novel tumor markers for this form of cancer. Additionally, the role of type IV collagen produced by the cancer cells is studied. Methods: Expression patterns of type IV and type XVIII collagen, MMPs involved in collagen degradation, and collagen receptors (integrins) were studied by immunoflourescence in both normal and pancreatic cancer tissue, and in pancreatic cancer cell lines. Circulating plasma levels of type IV and type XVIII collagen and conventional tumor markers (TPS, Ca 19-9, CEA and Ca 125) were measured in controls and pancreatic cancer patients at the time of diagnosis and after treatment. The role of cancer cell produced type IV collagen was studied in human pancreatic cancer cell lines by functional blocking of integrin receptors (integrin a1, a2 and b1) and integrin-binding sites on type IV collagen, and by siRNA-induced down-regulation of type IV collagen synthesis. Proliferation was analyzed by a luminescence based cell viability assay, migration by time-lapse microscopy, and apoptosis by M30-neoepitope detection. Results: MMPs involved in BM degradation were upregulated in pancreatic cancer tissue. The expression of type XVIII collagen shifted from a general BM expression pattern in normal tissue, to mainly being found in the tumor vasculature in pancreatic cancer. Type IV collagen, on the other hand, remained highly expressed in the vicinity of the cancer cells. The a1, a2, and b1 integrin receptors were highly expressed at the cancer cell surface. Both down-regulation of type IV collagen synthesis and blocking the integrin/type IV collagen interaction decreased cell proliferation and migration. The proliferative capacity was rescued by the addition of exogenous type IV collagen. Furthermore, the circulating levels of both type IV and type XVIII collagen were increased in pancreatic cancer patients at the time of diagnosis compared to controls. After treatment, the levels were normalized for type XVIII collagen, whereas the levels of type IV collagen remained high after surgery. High postoperative levels of type IV collagen were associated with short overall survival. A similar association to short survival was found for preoperative type XVIII collagen levels. No such associations to survival could be detected for the conventional markers.   Conclusion: The results of this thesis show that type IV and type XVIII collagens can serve as tumor markers for pancreatic cancer with advantages compared to conventionally used markers. Additionally, evidence is provided of an autocrine loop, involving type IV collagen and its integrin receptors, with importance for retaining a proliferative and migratory phenotype in pancreatic cancer cells.

No description available.

Le renouvellement de la membrane basale et de la matrice extracellulaire lors de processus physiologiques ou pathologiques (réparation tissulaire, angiogenèse, inflammation, cancer) fait intervenir de nombreuses protéases dont les cathepsines à cystéine. Après avoir étudié leur localisation dans l’épiderme à proximité de la jonction dermo-épidermique et leur sécrétion par les kératinocytes, nous avons montré la capacité de la cathepsine S à dégrader efficacement les principales protéines de la membrane basale (laminine, collagène IV, perlécan) et plus particulièrement le nidogène-1, qui est essentiel à l’organisation architecturale de la membrane basale via de multiples interactions avec les autres constituants. Parmi plusieurs glycosaminoglycanes présents dans la matrice extracellulaire, le chondroïtine 4-sulfate est capable de se complexer avec la cathepsine S, via trois sites potentiels de fixation dont un au niveau de son site actif, et d’inhiber son activité enzymatique de façon dose-dépendante. L’expression et l’activité de la cathepsine S au niveau de l’épiderme diminuent au cours du vieillissement cutané, alors que l’expression du nidogène-1 reste stable. La cathepsine S jouerait donc un rôle important aux côtés d’autres protéases dans le remodelage de la membrane basale. / Basement membrane (BM) and extracellular matrix (ECM) turnover during physiological or pathological events (tissue repair, angiogenesis, inflammation, cancer) involves numerous proteases including cysteine cathepsins. Cathepsins expression in skin epidermis near dermal-epidermal junction and their secretion by keratinocytes were first analyzed. We showed that cathepsin S degrades efficiently main BM components (laminin, type IV collagen, perlecan) and particularly nidogen-1 that is essential for BM architecture. Among several glycosaminoglycans present in ECM, chondroïtin 4-sulfate is able to form a stable complex with cathepsin S. Three predicted binding sites including one closed to its active site were identified. Further, C4-S inhibits cathepsin S activity in a dose-dependent manner. The expression and activity of cathepsin S in epidermis are decreased upon skin aging while nidogen-1 expression remains unchanged. Cathepsin S besides other proteases may play an important role in BM remodeling.

INTRODUÇÃO: Embora seja reconhecida a existência do espessamento da membrana basal e da fibrose da concha nasal na rinite alérgica, não há estudos descritivos do comportamento da mucosa nasal nos pacientes com rinite idiopática. O propósito desse estudo é descrever possíveis alterações na membrana basal e na lâmina própria da concha nasal inferior em pacientes com rinite alérgica ou idiopática, além do estudo quantitativo das fibras colágenas nesta localização. MÉTODOS: Analisou-se na concha nasal inferior obtida através de turbinectomia bilateral em 28 pacientes - 14 com rinite alérgica e 14 com rinite idiopática - a área ocupada pelo colágeno, a espessura da membrana basal e o diâmetro das fibrilas de colágeno através do uso de microscopia óptica (coloração Hematoxilina-eosina e Picrossírius-hematoxilina), microscopia eletrônica e imunoistoquímica para laminina e colágeno IV. RESULTADOS: 1) pacientes com rinite alérgica apresentaram significantemente maior área da concha nasal ocupada por colágeno do que o grupo com rinite idiopática. 2) a membrana basal de pacientes com rinite alérgica foi significantemente mais espessa. 3) a lâmina reticular da membrana basal dos pacientes com rinite alérgica apresentaram fibrilas de colágeno com menor diâmetro que os pacientes com rinite idiopática. 4) não houve diferenças significativas entre os grupos na distribuição de laminina e de colágeno IV. CONCLUSÕES: Alterações na mucosa nasal ocorrem na rinite alérgica, sendo caracterizadas pelo aumento da espessura da membrana basal e por fibrose. Na rinite idiopática, observou-se uma mucosa com aspecto estrutural semelhante aos pacientes normais / INTRODUCTION: Despite our knowledge about nasal conchae fibrosis and basement membrane thickening in allergic rhinitis, there are no descriptive studies on nasal mucosa behavior in patients with idiopathic rhinitis. The aim of our study was to describe possible changes in the basement membrane and lamina propria of the inferior concha in patients with idiopathic or allergic rhinitis, in addition to a quantitative study of collagen fibers in this site. METHODS: The inferior nasal concha obtained from 28 patients submitted to bilateral turbinectomy was examined - 14 with allergic rhinitis and 14 with idiopathic rhinitis; analyzing the collagen area, the basement membrane thickness and the collagen fibrils diameter using optical microscopy (Hematoxylin-eosin and Picrosirius-hematoxylin staining), electron microscopy and immunohistochemistry for laminin and collagen IV. RESULTS: 1) patients with allergic rhinitis had a significantly larger area of the nasal concha occupied by collagen than the group with idiopathic rhinitis. 2) the basement membrane of patients with allergic rhinitis was significantly thicker. 3) the reticular lamina of the basement membrane of patients with allergic rhinitis had collagen fibrils with diameters which were smaller than those from patients with idiopathic rhinitis. 4) there were no significant differences between the groups concerning the distribution of laminin and collagen IV. CONCLUSIONS: Alterations to the nasal mucosa that happen in allergic rhinitis are characterized by basement membrane thickening and fibrosis. In idiopathic rhinitis the patients\' mucosae were structurally similar to those from normal patients

Abstract It is a generally accepted dogma that sepsis disturbs skin function and wound healing, but surprisingly there is only remote pathophysiological evidence available behind that presumption. As the skin is the largest defensive barrier, the skin dysfunction in severe sepsis deserves more attention. In this study, the suction blister model was used to create experimental wounds. The study population included 44 patients with severe sepsis and 15 controls. The blister fluid was collected to analyse cytokine profile of the skin. The transepidermal water loss and blood flow from the wound were measured. A 4mm biopsy was taken under local anaesthesia on the first and the eighth day of the study from the healthy looking skin. Then 15 healing suction blisters were excised. Serum samples were also collected on the first day of the study. The barrier restoration was diminished, and the inflammation in the wound was more intense in severe sepsis than in the controls. The expression of the basement membrane components Laminin-332 and type IV collagen decreased during the septic disease, but increased over the next 3 months without achieving the level oft he controls. The expression of tight junction proteins remained nearly intact in the healing wound in severe sepsis compared to the controls. The expression of occludin on the leading edge of the migrating keratinocytes was more restricted and late in severe sepsis compared to the controls. The levels of the tumour necrosis factor (TNF), interleukin-10 (IL-10) and IL-6 in skin blister fluid were higher in the sepsis compared to controls. The blister fluid and serum cytokine response in the sepsis differed since the levels of epidermal growth factor, vascular endothelial growth factor, TNF and basic fibroblastic growth factor (bFGF) in the blister fluid did not correlate with the levels of serum. The septic patients with multiple organ failure had higher levels of several cytokines than patients without organ failure. Survivors had lower levels of IL-10 and bFGF in blister fluid than the non-survivors. This study offers novel findings for skin and wound healing in sepsis. Together, all the findings suggest that skin dysfunction in severe sepsis exists even when the most profound structures remain intact. Understanding these mechanisms of impaired wound healing can improve future treatments, such as the timing of surgery. / Tiivistelmä Sepsiksen ajatellaan heikentävän haavanparanemista, mutta tieteellistä näyttöä on niukasti. Iholla on keskeinen osa elimistön puolustuksessa ja tasapainon ylläpidossa, joten sen toiminnan häiriintyminen systeemisessä tulehduksessa ansaitsee suuremman huomion. Imurakkulahaavat tehtiin 44 septiselle potilaalle ja 15 kontrollille. Haavoista mitattiin veden haihtumista ja veren virtausta sekä otettiin imurakkulaneste näytteeksi sytokiinimäärityksiä varten. Tutkimuksen ensimmäisenä ja kahdeksantena päivänä otettiin 4mm biopsiat terveeltä iholta ja 15 potilaalta poistettiin näytteeksi paraneva imurakkulahaava. Seeruminäytteet otettiin tutkimuksen ensimmäisenä päivänä. Veden haihtuminen haavalta oli voimakkaampaa eli ihon barrierin palautuminen oli hidastunut septisillä potilailla verrattuna kontrolleihin. Haavassa havaittu tulehdus oli sepsiksessä voimakkaampi. Tyvikalvon komponenttien Laminiini-332:n ja tyypin IV kollageenin ilmentyminen oli vähäisempää sepsiksen aikana ja lisääntyi 3kk kohdalla, mutta ei kuitenkaan saavuttanut kontrollien tasoa. Tiivisliitosproteiinien ilmentyminen oli lähes muuttumatonta sepsiksessä kontrolleihin verrattuna. Okludiinin ilmentyminen sen sijaan paranevassa haavassa vaeltavien keratinosyyttien etureunassa oli rajoittuneempaa ja myöhäisempää sepsiksessä kuin kontrolleilla. Sytokiineistä tuumorinekroositekijä (TNF), interleukiini-10 (IL-10) ja IL-6 olivat koholla imurakkulanesteessä verrattuna kontrolleihin. Epidermaalinen kasvutekijä, verisuonten endoteelikasvutekijä, TNF ja perusfibroplastinen kasvutekijä (bFGF) pitoisuudet rakkulanesteessä erosivat seerumin pitoisuuksista eli ihon sytokiiniprofiili erosi systeemisestä sytokiiniprofiilista. Potilailla, joilla oli monielinvaurio, todettiin korkeampia sytokiinipitoisuuksia. Potilailla, jotka menehtyivät 30 vrk kuluessa, oli korkeammat pitoisuudet IL-10 ja bFGF rakkulanesteessä. Tämä tutkimus tarjoaa uutta tietoa ihosta ja haavanparanemisesta sepiksessä. Tulosten perusteella voidaan todeta, että ihon toimintahäiriö on sepsiksessä todellinen, vaikka kaikkein perustavimmat rakenteet säilyvät muuttumattomina. Toimintahäiriön mekanismien ymmärtäminen voisi auttaa septisen potilaan hoidossa, kuten kirurgisten toimenpiteiden ajoittamisessa paranemisen kannalta mahdollisimman otolliseen aikaan.

Les membranes basales (MB) jouent un rôle majeur au cours des processus morphogénétiques. Elles et sont principalement composées de Collagène de type IV, de Perlecan et de Laminine. Les récepteurs d'adhésions/signalisations (Intégrines/Dystroglycans) localisés au pôle basal des cellules épithéliales, interagissent directement avec les MBs. De nombreuses études montrent l'importance de la composition des MBs dans le devenir cellulaire. Cependant, le rôle mécanique de la MB au cours du développement d'un organe multicouche n'est pas connu. Comme modèle de morphogenèse épithéliale, nous avons choisi d'étudier l'épithélium du follicule ovarien chez Drosophila melanogaster. La MB entoure chaque follicule ovarien qui est composé d'une monocouche de cellules épithéliales cuboïdes entourant un groupe interne formé de 16 cellules de la lignée germinale (15 cellules nourricières en postérieur et 1 ovocyte en antérieur). Au cours du développement folliculaire, les cellules épithéliales s'aplatissent suivant une vague antéro-postérieur. Cette transition cellulaire cuboïde – aplatie dépend du remodelage des jonctions d'adhérence et du cytosquelette. Mes travaux de thèse ont porté sur l'étude du rôle mécanique et moléculaire de la MB au cours de la morphogenèse épithéliale chez la Drosophile. J'ai ainsi pu montrer (i) que la rigidité de la MB augmente au fur et à mesure du développement du follicule, (ii) que l'aplatissement dépend de la structure de la MB et de la liaison a cette MB grâce aux intégrines (iii) que la MB s'assouplie lors de la transition cuboïde-squameux et que cette assouplissement dépend de ce processus. Ces résultats démontrent un dynamisme mécanique et moléculaire de la MB au cours de l'ovogenèse et de la morphogenèse, révélant le rôle central de la MB lors de ces processus. Parallèlement j'ai développé une approche par segmentation cellulaire afin d'extraire les valeurs métriques (hauteur, anisotropie, surface basale, volume) des cellules épithéliales et de mesurer les variations de ces paramètres au cours de la morphogenèse épithéliale (MARS-ALT) / Epithelial cell morphogenesis is an essential process for animal development. Epithelia are composed of polarized cells with a basal side interacting through Integrins, with a basement membrane (BM) and a lateral side containing cadherin-based junctional complexes. Integrins and Cadherins are, both, linked to actin filaments and are thus involved in cell shape regulation. While these links are well documented, it remains unclear how the components of the BM and the 3D organisation of this tissue influence epithelial cell morphogenesis. The model we are using to study this influence is the follicular epithelium in Drosophila melanogaster. It consists of a monolayer of 800 epithelial cells surrounding the egg chamber consisted of an internal cluster of 16 germline cells (15 nurse cells and one posteriorly-localized oocyte). An extracellular matrix (ECM), composed mainly of Collagen IV and Laminins, surrounds each follicle, directly secreted by follicular cells. During follicle development, the cuboidal epithelial cells become squamous around the nurse cells and columnar around the oocyte. The cuboidal-to-squamous transition depends on both Integrins (formed by the subunits aPS2/bPS) and Cadherin-based adherens junction remodelling. Here we designed an Atomic Force Microscopy (AFM) approach to investigate the elastic modulus of the ECM in a living ovarian follicle at different stages of development and particularly during epithelial cell morphogenesis. First, we found that the stiffness changes temporally during oogenesis with an increase of stiffness during Collagen IV deposition. Second, during cell morphogenesis, we observed a gradient of ECM stiffness. Third, by measuring the stiffness in mutants delaying or promoting cell flattening, we showed that the regional differences occurs in function of the cell ability to flatten. Fourth, to assess the involvement of Collagen IV or its structure for the ECM rigidity properties, we measured the stiffness of ECM produced by follicles mutant for Collagen IV or after collagenase treatment and concluded that collagen fibrils are the source of rigidity properties.Altogether, these results demonstrate the role of the regulation of the ECM stiffness for epithelial cell morphogenesis and highlight a new mechanical aspect in the comprehension of developmental processes

Au cours de l'obésité, le Tissu Adipeux blanc (TAB) est le siège d'un important remaniement de sa Matrice Extracellulaire avec des amas fibrotiques autour des adipocytes et des vaisseaux. Cette organisation caractéristique semble avoir une incidence dans la physiopathologie de l'obésité. Les composés spécifiques à la Membrane Basale ont été mis en évidence autour des adipocytes et des cellules endothéliales et leur expression est fortement induite dans l'adipocyte obèse. L'expression de COL4A1 est positivement corrélée à l'insulino-résistance de sujets présentant une obésité modérée. De plus, dans un autre groupe de sujets massivement obèses candidats à la chirugie bariatrique, la diminution de l'expression génique de COL4A1 est à relier avec l'amélioration de l'insulino-résistance après l'intervention. Enfin, nous observons que, dans le TAB, l'expression de COL4A1 est positivement associée à l'expression génique de deux facteurs de croissance pro-fibrotiques, le TGF 1 et le TGF 3, dans le TAB. La culture tridimensionnelle d'adipocytes ou de cellules endothéliales exposés à ces deux facteurs induit un phénotype fibro-inflammatoire dans ces types cellulaires. Néanmoins, le traitement par le TGF 1 ou TGF 3 induit uniquement dans les cellules endothéliales une sur-expression de COL4A1 et non dans les adipocytes.En conclusion, nos données proposent un nouvel acteur de la fibrose du TAB au cours de l'obésité, la Membrane Basale adipocytaire et vasculaire, participant ainsi à la dysfonction tissulaire et métabolique. / During obesity, White Adipose Tissue (WAT) undergoes an important remodeling of its Extracellular Matrixwith fibrotic depots around adipocytes and vessels. This typical organization seems to have an impact in the pathophysiology of obesity. Basement Membrane components were detected around adipocytes and endothelial cells and their expression were significantly increased in obese adipocytes. COL4A1 expression in WAT is positively correlated to insulin-resistance parameters in moderate obese subjects, and its reduction is associated to insulin-resistance improvement after gastric bypass in a group of morbidly obese subjects. Finally, we demonstrated a postive correlation between COL4A1 expression and two pro-fibrotic growth factor (TGF1 and TGF3) in obese WAT. In vitro treatment of isolated adipocytes and endothelial cells with these TGF isoforms induced inflammatory and fibrotic phenotype. However, TGF1 and TGF3 exposure only provoked COL4A1 over-expression in endothelial cells, and not in adipocytes. In conclusion, our work have highlighted a new actor in WAT fibrosis during obesity, adipocytes and endothelial cells Basement Membrane, participating in the pathological alterations of obese adipose tissue and metabolism.

Kollagen IV assoziierte Nephropathien sind hereditäre Erkrankungen, die die glomeruläre Basalmembran betreffen. Homozygote Aberrationen des COL4A3- oder des COL4A4-Gens zeigen wie X-chromosomal dominant vererbte Mutationen des COL4A5-Gens das klinische Bild des Alport-Syndroms mit frühzeitigem terminalem Nierenversagen. Heterozygote COL4A3-Mutationen sind ursächlich für die benigne familiäre Hämaturie. Ein zusätzlicher Polymorphismus in Nphs2, welches das Schlitzmembranprotein Podocin kodiert, könnte hierbei zu einem aggravierten Krankheitsverlauf führen. Um diese These zu überprüfen, ist eine Analyse des glomerulären Filters, bestehend aus glomerulärer Basalmembran, der zwischen den Podozytenfüßen liegenden Schlitzmembran und Kapillarendothel notwendig. Nidogen-2 ist als Verbindungsprotein essenzieller Bestandteil der glomerulären Basalmembran. Die Ergebnisse der Untersuchungen des Proteins in der Basalmembran COL4A3 heterozygoter Mäuse mit zusätzlichem Podocin-Polymorphismus wichen stark von denen bei einfach COL4A3 heterozygoten Tieren ab. Es ergeben sich daher anhand von Nidogen-2 Hinweise, dass eine Mutation in Nphs2 den Krankheitsverlauf Kollagen IV assoziierter Erkrankungen modifizieren könnte.

Les cellules épithéliales qui produisent l’émail, les améloblastes, sont séparées de l'émail au niveau de la zone de maturation par une membrane basale spécialisée (MBS) enrichie en laminine 332 (LM-332). Cette protéine hétérotrimérique (composée des chaînes α3, ß3 et γ2) assure l'intégrité structurelle des membranes basales (MB) et influence divers processus cellulaires épithéliaux tels que l'adhésion et la différenciation cellulaire. Des modèles de souris « knockout » (KO), où les gènes codant pour LM-332 ont été supprimés, meurent peu après la naissance. Néanmoins, ce phénotype létal peut être contourné en substituant chez la souris le gène produisant la chaîne γ2 de la laminine (LAMC2) par sa forme humaine, sous le contrôle de l’expression du promoteur-rtTA, de la cytokératine 14, inductible par la prise de doxycycline (Dox) - (Tet-on). Le but de ce projet est d’examiner si l’utilisation de cette protéine humaine chez la souris a un effet sur la structuration de la MBS ainsi que sur la maturation de l'émail. La phase de maturation de l’organe de l’émail chez la souris transgénique a été sévèrement altérée par rapport à une souris normale (WT). La MBS n’est plus visible, une matrice dystrophique s’est formée dans la couche d'émail dans la phase de maturation, et la présence d’une matrice résiduelle de l'émail est observée durant la phase tardive de maturation. Des micro-analyses tomographiques ont révélé une usure excessive des surfaces occlusales des molaires, un écroulement de l'émail sur les pointes des incisives et une hypominéralisation de l'émail. Cependant, aucune altération structurale due à cette recombinaison transgénique n’a été observée dans d'autres sites épithéliaux, tels que la peau, le palais et la langue. Ces résultats indiquent que, bien que ce modèle de souris humanisée soit capable de rétablir ses fonctions dans divers tissus épithéliaux, il est incapable de soutenir la structuration d'une MBS à l'interface entre les améloblastes et l’émail en maturation. Cet échec peut être lié à la composition spécifique de la MBS dans la phase de maturation et supporte l’hypothèse que la MBS est essentielle pour la maturation adéquate de l'émail. / The epithelial ameloblasts are separated from the maturing enamel by an atypical basement membrane (BM) that is enriched in laminin 332 (LM-332). This heterotrimeric protein (α3, ß3 and γ2 chains) provides structural integrity to BMs and influences various epithelial cell processes including cell adhesion and differentiation. Mouse models that lack expression of individual LM-332 chains die shortly after birth. The lethal phenotype of laminin γ2 knockout mice can be rescued by human laminin γ2 (LAMC2) expressed using a doxycycline-inducible (Tet-on) cytokeratin 14 promoter-rtTA. These otherwise normal-looking rescued mice exhibit white spot lesions on incisors. We therefore investigated the effect of rescue with human LAMC2 on enamel maturation and structuring of the atypical BM. The maturation stage enamel organ in transgenic mice was severely altered as compared to wild type controls, a structured BM was no longer discernible, dystrophic matrix appeared in the maturing enamel layer, and there was residual enamel matrix late into the maturation stage. Microtomographic scans revealed excessive wear of occlusal surfaces on molars, chipping of enamel on incisor tips, and hypomineralization of the enamel layer. No structural alterations were observed at other epithelial sites, such as skin, palate and tongue. These results indicate that while this humanized mouse model is capable of rescue in various epithelial tissues, it is unable to sustain structuring of a proper BM at the interface between ameloblasts and maturing enamel. This failure may be related to the atypical composition of the BM in the maturation stage and reaffirms that the atypical BM is essential for enamel maturation.

INTRODUÇÃO: Os pacientes com asma crônica podem compartilhar similaridades clínicas e fisiológicas com pacientes com doença pulmonar obstrutiva crônica, tal como reversibilidade parcial ao broncodilatador ou pouca obstrução persistente do fluxo expiratório. Entretanto, não existem estudos comparando a patologia destas duas doenças em pacientes com idade similares e mesma gravidade da doença. MÉTODOS: Nós comparamos as dimensões das grandes e pequenas vias aéreas de 12 pacientes adultos (média±erro padrão, 32±3 anos) e 15 pacientes idosos e pré-idosos idosos (65±1 ano) não tabagista que foram a óbito por asma fatal com 14 pacientes tabagistas crônicos que foram a óbito por DPOC grave (71± 1 ano) e 19 pacientes-controle (56±1 ano). Usando a coloração de Movat e H&E, e a técnica de análise de imagens, nós quantificamos a espessura da membrana basal (MB) (valores expressos em ?m) a área de glândula submucosa nas grandes vias aéreas. Nas grandes e pequenas vias aéreas quantificamos a área de camada interna, a área de músculo liso e a área de camada externa. As áreas foram normalizadas pelo perímetro da MB (?m/?m2). RESULTADOS: os pacientes asmáticos adultos apresentaram a MB, área de músculo liso e a área da camada externa nas grandes e pequenas vias aéreas mais espessas, quando comparadas com os controles com idade similar com DPOC grave. Nos pacientes idosos e pré-idosos com asma, houve uma sobreposição na espessura da MB e na área da glândula submucosa, enquanto que nas pequenas e grandes vias aéreas a área de músculo liso foi mais espessa quando comparados com os controles com idade similar com pacientes com DPOC grave. Os pacientes com DPOC apresentaram nas pequenas e grandes vias aéreas as áreas de músculo liso menor quando comparada aos controles com idade similar. Os asmáticos adultos apresentaram a área de músculo liso maior quando comparada aos asmáticos idosos. CONCLUSÃO: Nossos dados fornecem novas informações sobre as mudanças patológicas que podem nos ajudar a entender melhor as similaridades e diferenças patológicas no pacientes adultos e idosos com asma comparados ao DPOC / Background: In some patients with chronic asthma, clinical and physiological similarities with chronic obstructive pulmonary disease may co-exist, such as partial reversibility to bronchodilators despite persistent expiratory airflow obstruction. However, pathologic analyses comparing both diseases in patients of similar age and disease severity are scarce. Methods: We compared the large and small airway dimensions in 12 younger (mean±SD, age 32 yr±3 yr) and 15 older (65 yr±1 yr) non-smoking fatal asthmatics with 14 chronic smokers with severe, fatal COPD (71 yr±1 yr) and 19 control patients (56 yr±1 yr). Using H&E, Movat\'s pentachrome staining and image analysis, we quantified large airway basement membrane (BM) thickness (?m); submucosal gland area; and large and small airway inner wall, smooth muscle and outer wall areas. Areas were normalized by BM perimeter (?m2/?m). Results: Younger adult fatal asthmatics had thicker BM, smooth muscle, and outer wall areas in both small and large airways when compared to agematched controls and fatal COPD patients. In older asthmatics, there was an overlap in BM thickness and submucosal gland area, whereas both large and small airway smooth muscle areas were thicker compared to age-matched controls and fatal COPD patients. COPD patients had thinner large and small airway smooth muscle areas compared to age-matched controls. Younger asthmatics had thicker small airway smooth muscle area compared to older asthmatics. Conclusion: Our data provide novel pathological substrate changes that may help us better understand physiological similarities and differences in younger and older patients with asthma compared to COPD.