A patogênese da Fibrose Pulmonar Idiopática (FPI/PIU), doença fibroproliferativa crônica, é caracterizada por um processo de reparação anormal com acentuada deposição de matriz extra celular. Neste contexto, a importância das alterações vasculares na evolução da FPI/PIU permanece controversa.O presente estudo objetiva quantificar as alterações histopatológicas da macro e microcirculação pulmonar na FPI/PIU e seu valor prognóstico. Foram avaliados retrospectivamente as biópsias pulmonares e a sobrevida de 36 pacientes com FPI/PIU. Na biópsia pulmonar, as lesões do parênquima foram analisadas através da quantificação do grau de atividade fibrogênica (leve, moderado e acentuado). A quantificação das alterações vasculares foi feita isoladamente nas áreas normais, de colapso alveolar e de fibrose mural organizante. A macrocirculação foi estudada através da análise semiquantitativa das artérias pré acinares quanto ao grau de lesão vascular, grau de oclusão e da espessura da parede do vaso, e quantificação de fibras elásticas e de colágeno vasculares. No estudo da microcirculação, os capilares foram analisados quanto a densidade capilar, através de imunomarcador endotelial (CD34), e a disfunção endotelial, através do aumento da expressão de moléculas de adesão (VCAM1, ICAM1, E-Selectina). As biópsias de 5 pulmões normais foram utilizadas como controles. À análise da macrocirculação, quanto maior o grau de atividade fibrogênica, mais acentuado foi o grau de lesão vascular (p=0,007), da espessura (p<0,05) e da quantificação de fibras de colágeno (p<0,001) e elástica (p=0,002) vasculares. Quanto à microcirculação, a densidade microvascular (CD34) nas áreas de pulmão normal (p<0,001) e colapso alveolar (p<0,01) foram maiores que no grupo controle. Pacientes com atividade fibrogênica leve (p=0,2) e moderada (p=0,08) apresentaram tendência a aumento da densidade vascular nas áreas normais comparados aos pacientes com atividade fibrogênica acentuada. A disfunção endoletial (VCAM1, ICAM1 e E-selectina) foi maior em pacientes com FPI/PIU que em controles normais (p<0,05), e ocorreu, principalmente, nas áreas de fibrose mural organizante. A disfunção endotelial (VCAM1+) nas áreas normais aumentou conforme maior o grau de atividade fibrogênica (p=0,01). Pacientes com maior quantificação de fibras de colágeno e elástica na parede do vaso (p=0,04; p=0,03; Teste Log Rank) e maior disfunção endotelial (VCAM1+) nas áreas fibrose mural organizante (p=0,027) apresentaram menor sobrevida. A maior densidade microvascular nas áreas não fibróticas correlacionou-se com sobrevida maior (p=0,04). Observamos a existência de remodelamento vascular na macro e microcirculação pulmonar dos pacientes com fibrose pulmonar idiopática que ocorre de maneira heterogênea e paralela ao remodelamento parenquimatoso. Essas alterações correlacionam-se com a sobrevida, permitindo formular uma hipótese de participação dos eventos vasculares na patogênese da FPI/UIP / The Idiopathic Pulmonary Fibrosis (IPF/UIP), a chronic fibroproliferative disease, is characterized by a process of impaired wound healing with extracellular matrix deposition. In this context, the importance of the vascular alterations in the evolution of IPF/UIP remains controversial. The present study aims to quantify the histopatological alterations in the pulmonary macro and microcirculation in IPF/UIP and their prognostic value. Pulmonary biopsies and the survival of 36 patients with IPF/UIP were evaluated retrospectivately. In the pulmonary biopsy, the parenchyma remodeling was analyzed through the quantification of the fibrogenic activity level (minimal, moderate and severe). The quantification of the vascular alterations was done isolately in the normal, alveolar collapsed and mural-organizing fibrosing areas. The macrocirculation was studied through the semiquantitative analysis of pre acinar artery, according to the degree of vascular lesion, occlusion and thickness of the vessel wall, and quantification of vascular collagen and elastic deposition. Microcirculation analysis was performed measuring capillary density (CD34), and endothelial dysfunction (VCAM1, ICAM1, E-Selectina). The biopsies of 5 normal lungs were used as control. Macrocirculation analysis showed that degree of fibrogenic activity directly correlated with: degree of vascular lesion (p=0,007), thickness of vessel wall (p<0,05) and quantification of vascular collagen (p<0,001) and elastic fibers (p=0,002). Regarding microcirculation, the capillary vascular density (CD34) in normal (p<0,001) and alveolar collapsed (p<0,01) areas were higher than control group. Patients with minimal (p=0,2) and moderate (p=0,08) fibrogenic activity had a tendency to higher vascular density in normal areas compared to patients with severe fibrogenic activity. The endothelial dysfunction (VCAM1, ICAM1, E-selectina) was more intense in patients with IPF/PIU than normal controls (p<0,05), and it occurred, mainly, in mural-organizing fibrosing areas. In normal areas, endothelial dysfunction (VCAM1+) correlated with the degree of fibrogenic activity (p=0,01). Shorter survival correlated with collagen and elastic fibers deposition in wall vessels (p=0,04; p=0,03 Test Log Rank) and endothelial dysfunction (VCAM1+) in mural-organizing fibrosing areas (p=0,027), while microvascular density in non-fibrotic areas was related to longer survival (p=0,04). We observed the presence of vascular remodeling in pulmonary macro and microcirculation of IPF patients, which occurs in a heterogeneous and parallel way with parenchyma remodeling. These alterations were related to survival, enabling us to formulate a hypothesis of the participation of vascular events on IPF pathogenesis

A patogênese da Fibrose Pulmonar Idiopática (FPI/PIU), doença fibroproliferativa crônica, é caracterizada por um processo de reparação anormal com acentuada deposição de matriz extra celular. Neste contexto, a importância das alterações vasculares na evolução da FPI/PIU permanece controversa.O presente estudo objetiva quantificar as alterações histopatológicas da macro e microcirculação pulmonar na FPI/PIU e seu valor prognóstico. Foram avaliados retrospectivamente as biópsias pulmonares e a sobrevida de 36 pacientes com FPI/PIU. Na biópsia pulmonar, as lesões do parênquima foram analisadas através da quantificação do grau de atividade fibrogênica (leve, moderado e acentuado). A quantificação das alterações vasculares foi feita isoladamente nas áreas normais, de colapso alveolar e de fibrose mural organizante. A macrocirculação foi estudada através da análise semiquantitativa das artérias pré acinares quanto ao grau de lesão vascular, grau de oclusão e da espessura da parede do vaso, e quantificação de fibras elásticas e de colágeno vasculares. No estudo da microcirculação, os capilares foram analisados quanto a densidade capilar, através de imunomarcador endotelial (CD34), e a disfunção endotelial, através do aumento da expressão de moléculas de adesão (VCAM1, ICAM1, E-Selectina). As biópsias de 5 pulmões normais foram utilizadas como controles. À análise da macrocirculação, quanto maior o grau de atividade fibrogênica, mais acentuado foi o grau de lesão vascular (p=0,007), da espessura (p<0,05) e da quantificação de fibras de colágeno (p<0,001) e elástica (p=0,002) vasculares. Quanto à microcirculação, a densidade microvascular (CD34) nas áreas de pulmão normal (p<0,001) e colapso alveolar (p<0,01) foram maiores que no grupo controle. Pacientes com atividade fibrogênica leve (p=0,2) e moderada (p=0,08) apresentaram tendência a aumento da densidade vascular nas áreas normais comparados aos pacientes com atividade fibrogênica acentuada. A disfunção endoletial (VCAM1, ICAM1 e E-selectina) foi maior em pacientes com FPI/PIU que em controles normais (p<0,05), e ocorreu, principalmente, nas áreas de fibrose mural organizante. A disfunção endotelial (VCAM1+) nas áreas normais aumentou conforme maior o grau de atividade fibrogênica (p=0,01). Pacientes com maior quantificação de fibras de colágeno e elástica na parede do vaso (p=0,04; p=0,03; Teste Log Rank) e maior disfunção endotelial (VCAM1+) nas áreas fibrose mural organizante (p=0,027) apresentaram menor sobrevida. A maior densidade microvascular nas áreas não fibróticas correlacionou-se com sobrevida maior (p=0,04). Observamos a existência de remodelamento vascular na macro e microcirculação pulmonar dos pacientes com fibrose pulmonar idiopática que ocorre de maneira heterogênea e paralela ao remodelamento parenquimatoso. Essas alterações correlacionam-se com a sobrevida, permitindo formular uma hipótese de participação dos eventos vasculares na patogênese da FPI/UIP / The Idiopathic Pulmonary Fibrosis (IPF/UIP), a chronic fibroproliferative disease, is characterized by a process of impaired wound healing with extracellular matrix deposition. In this context, the importance of the vascular alterations in the evolution of IPF/UIP remains controversial. The present study aims to quantify the histopatological alterations in the pulmonary macro and microcirculation in IPF/UIP and their prognostic value. Pulmonary biopsies and the survival of 36 patients with IPF/UIP were evaluated retrospectivately. In the pulmonary biopsy, the parenchyma remodeling was analyzed through the quantification of the fibrogenic activity level (minimal, moderate and severe). The quantification of the vascular alterations was done isolately in the normal, alveolar collapsed and mural-organizing fibrosing areas. The macrocirculation was studied through the semiquantitative analysis of pre acinar artery, according to the degree of vascular lesion, occlusion and thickness of the vessel wall, and quantification of vascular collagen and elastic deposition. Microcirculation analysis was performed measuring capillary density (CD34), and endothelial dysfunction (VCAM1, ICAM1, E-Selectina). The biopsies of 5 normal lungs were used as control. Macrocirculation analysis showed that degree of fibrogenic activity directly correlated with: degree of vascular lesion (p=0,007), thickness of vessel wall (p<0,05) and quantification of vascular collagen (p<0,001) and elastic fibers (p=0,002). Regarding microcirculation, the capillary vascular density (CD34) in normal (p<0,001) and alveolar collapsed (p<0,01) areas were higher than control group. Patients with minimal (p=0,2) and moderate (p=0,08) fibrogenic activity had a tendency to higher vascular density in normal areas compared to patients with severe fibrogenic activity. The endothelial dysfunction (VCAM1, ICAM1, E-selectina) was more intense in patients with IPF/PIU than normal controls (p<0,05), and it occurred, mainly, in mural-organizing fibrosing areas. In normal areas, endothelial dysfunction (VCAM1+) correlated with the degree of fibrogenic activity (p=0,01). Shorter survival correlated with collagen and elastic fibers deposition in wall vessels (p=0,04; p=0,03 Test Log Rank) and endothelial dysfunction (VCAM1+) in mural-organizing fibrosing areas (p=0,027), while microvascular density in non-fibrotic areas was related to longer survival (p=0,04). We observed the presence of vascular remodeling in pulmonary macro and microcirculation of IPF patients, which occurs in a heterogeneous and parallel way with parenchyma remodeling. These alterations were related to survival, enabling us to formulate a hypothesis of the participation of vascular events on IPF pathogenesis

[Truncated abstract] Fibrosis is a feature of many pulmonary conditions, including idiopathic pulmonary fibrosis (IPF), which is characterised by the accumulation of fibroblasts/myofibroblasts and excessive deposition of collagen. IPF is a disease of unknown aetiology that is unresponsive to current therapy and is typically fatal. The inflammatory cytokine interleukin (IL)-6 is elevated in patients with IPF and recent studies have shown that IL-6-induced signalling is altered in lung fibroblasts from patients with IPF. IL-6 belongs to the gp130 cytokine family, which is a group of ten structurally related cytokines, that all require the membrane bound glycoprotein gp130 to activate intracellular signalling pathways. Gp130 activates intracellular signalling through the Shp2-ERK1/2 and STAT1/3 pathways to mediate cellular activities. This thesis tests the hypothesis that gp130-mediated signalling is dysregulated in the development and progression of pulmonary fibrosis. To address this hypothesis, I assessed the role of gp130-mediated signalling in a mouse model of bleomycin-induced lung fibrosis. This thesis utilised two novel gp130 mutant mice strains with directed and enhanced gp130-mediated Shp2-ERK1/2 (gp130¿STAT/¿STAT) or STAT1/3 (gp130757F/757F) signalling. I observed complete protection from fibrosis in gp130¿STAT/¿STAT mice up to 60 days after bleomycin treatment and profound fibrosis in gp130757F/757F mice compared to wt controls. The enhanced fibrosis observed in gp130757F/757F mice was diminished by monoallelic deletion of STAT3 (gp130757F/757F;STAT3+/-), identifying gp130-STAT3 signalling as a novel promoter of lung fibrosis. ... In addition, IL-6/11 activation of gp130-mediated signalling modulated transforming growth factor (TGF)-ß-induced effects on adult fibroblast proliferation and myofibroblast differentiation. Interaction between IL-6/11 and TGF-ß1 on fibroblast proliferation was dependent on both the gp130-ERK1/2 and gp130-STAT1/3 pathways. Loss of either pathway abrogated the effects of IL-6 and IL-11 on TGF-ß1- 4 induced fibroblast proliferation. However, it was clear that gp130-STAT3 signalling inhibited TGF-ß1-induced myofibroblast differentiation of primary lung fibroblasts. The inhibition of myofibroblast differentiation was associated with gp130-STAT3 dependent inhibition of TGF-ß1-induced Smad3 phosphorylation. These results indicate that IL-6 and IL-11 promote myofibroblastic differentiation of lung fibroblasts, while gp130-STAT3 signalling inhibits TGF-ß1-induced Smad3 phosphorylation and myofibroblastic differentiation of lung fibroblasts While the pathogenesis of IPF is unknown, it is believed that excessive collagen deposition, aberrant fibroblast behaviour and an inflammatory response are critical to the progression of this disease. It has been shown here that IL-6 family cytokines mediate the development and progression of bleomycin-induced lung fibrosis by increasing collagen synthesis, fibroblast proliferation, myofibroblast differentiation and inflammation through gp130-STAT3 signalling. This thesis has demonstrated that differential activation of cytoplasmic signalling pathways by a membrane bound receptor can have a profound effect on pulmonary responses to injury. Furthermore, this thesis is the first study to identify the gp130-STAT3 pathway as a therapeutic target in the treatment of IPF.