Unusual remodeling of the hyalinization band in vulval lichen sclerosus by type V collagen and ECM 1 protein

OBJECTIVES: The vulva is the primary site affected in lichen sclerosus, a chronic dermatosis in women that is histologically characterized by a zone of collagen remodeling in the superior dermis. The normal physiological properties of the vulva depend on the assembly of collagen types I (COLI), III (COLIII) and V (COLV), which form heterotypic fibers, and extracellular matrix protein interactions. COLV regulates the heterotypic fiber diameter, and the preservation of its properties is important for maintaining normal tissue architecture and function. In the current work, we analyzed the expression of COLV and its relationship with COLI, COLIII, elastic fibers and extracellular matrix protein 1 in vulvar biopsies from patients with lichen sclerosus. METHODS: Skin biopsies from 21 patients with lichen sclerosus, classified according to Hewitt histological criteria, were studied and compared to clinically normal vulvar tissue (N=21). Morphology, immunohistochemistry, immunofluorescence, 3D reconstruction and morphometric analysis of COLI, COLIII, COLV deposition, elastic fibers and extracellular matrix 1 expression in a zone of collagen remodeling in the superior dermis were performed. RESULTS: A significant decrease of elastic fibers and extracellular matrix 1 protein was present in the hyalinization zone of lichen sclerosus compared to healthy controls. The non-homogeneous distribution of collagen fibers visualized under immunofluorescence in the hyalinization zone of lichen sclerosus and control skin was confirmed by histomorphometry. Lichen sclerosus dermis shows a significant increase of COLI, COLIII and COLV expression compared to the healthy controls. Significant inverse associations were found between elastic fibers and COLV and between COLV and extracellular matrix 1 expression. A direct association was found between elastic fiber content and extracellular matrix 1 expression. Tridimensional reconstruction of the heterotypic fibers ...

Modeling pulmonary fibrosis by abnormal expression of telomerase/apoptosis/collagen V in experimental usual interstitial pneumonia

Limitations on tissue proliferation capacity determined by telomerase/apoptosis balance have been implicated in pathogenesis of idiopathic pulmonary fibrosis. In addition, collagen V shows promise as an inductor of apoptosis. We evaluated the quantitative relationship between the telomerase/apoptosis index, collagen V synthesis, and epithelial/fibroblast replication in mice exposed to butylated hydroxytoluene (BHT) at high oxygen concentration. Two groups of mice were analyzed: 20 mice received BHT, and 10 control mice received corn oil. Telomerase expression, apoptosis, collagen I, III, and V fibers, and hydroxyproline were evaluated by immunohistochemistry, in situ detection of apoptosis, electron microscopy, immunofluorescence, and histomorphometry. Electron microscopy confirmed the presence of increased alveolar epithelial cells type 1 (AEC1) in apoptosis. Immunostaining showed increased nuclear expression of telomerase in AEC type 2 (AEC2) between normal and chronic scarring areas of usual interstitial pneumonia (UIP). Control lungs and normal areas from UIP lungs showed weak green birefringence of type I and III collagens in the alveolar wall and type V collagen in the basement membrane of alveolar capillaries. The increase in collagen V was greater than collagens I and III in scarring areas of UIP. A significant direct association was found between collagen V and AEC2 apoptosis. We concluded that telomerase, collagen V fiber density, and apoptosis evaluation in experimental UIP offers the potential to control reepithelization of alveolar septa and fibroblast proliferation. Strategies aimed at preventing high rates of collagen V synthesis, or local responses to high rates of cell apoptosis, may have a significant impact in pulmonary fibrosis.

Remodelamento parenquimatoso pulmonar em dois modelos experimentais de fibrose / Parenchymal leing remodeling in two experimental models of fibroses

A fibrose pulmonar é a base patológica de uma variedade de doenças crônicas incuráveis. A IL-17A, uma glicoproteína secretada de células Th17, é uma citocina pró-fibrótica relacionada recentemente à síntese de colágeno V e fibrose pulmonar. O remodelamento parenquimatoso pulmonar da matriz extracelular pelo colágeno I e V, apoptose e resposta Th17 foi estudado em camundongos Balb/c, C57/B6J selvagens e com knockout para o receptor A da IL-17; para determinar as vias fisiopatológicas que prolongam a fase tardia do processo fibrótico induzido por bleomicina e paraquat. Microscopia eletrônica, imunofluorescência, imunohistoquímica, detecção in situ da apoptose, morfometria, reconstrução tridimensional e reação em cadeia da polimerase em tempo real foram usados para avaliar a quantidade, estrutura e cadeias moleculares dos tipos de colágenos, apoptose e células imunes. Verificamos um aumento da síntese e secreção do colágeno V que promove a perpetuação da fibrose pulmonar de maneira IL-17A dependente. Além disso, observou-se que marcadores críticos da resposta Th17 como IL17, STAT3, TGF-β, IL-6, IL- 21, IL-23 e células T CD4+ foram significantemente aumentados em cepas susceptíveis a fibrose pulmonar e intensificadas na ausência do receptor A da IL-17. O aumento de marcadores Th17 resulta em um aumento de células T CD4+ através de uma resposta imune que efetivamente bloqueia a degradação do colágeno V, o qual contribui para o bloqueio da apoptose...

Pulmonary fibrosis is the pathologic basis for a variety of incurable human chronic lung diseases. IL-17A, a glycoprotein secreted from IL-17– producing cells, has recently been shown to be a profibrotic cytokine involved in type V collagen synthesis and pulmonary fibrosis. Remodeling of the extracellular matrix by collagen I and V, cell death and Th-17 immune response were evaluated in Balb/c, wild and IL-17 receptor A knockout C57/B6J mice, to determine the pathways that prolong the late phase of the fibrotic process induced by bleomycin and paraquat. Electron microscopy, immunofluorescence, immunohistochemistry, in situ detection of apoptosis, morphometry, tridimensional reconstruction and a real-time PCR were used to evaluate the amount, structure and molecular chains of collagen types, apoptosis and immune cells. We verified increased synthesis and secretion of type V collagen that promoted the maintenance of pulmonary fibrosis in a IL-17A dependent manner. However, we observed that the critical Th17 markers, IL-17, STAT3, TGF-β, IL-6, IL-21, IL-23 and CD4+ T cells, were significantly increased in the fibrosis-susceptible strain and intensified in the absence of IL-17 receptor A. Increased Th17 markers resulted in an increase in CD4+ T cells in fibrotic lung tissue toward an immune response that effectively blocked degradation of collagen V, which contributes to block apoptosis...

Nasal tolerance with collagen v protein reverts bronchovascular axis remodeling in experimental bronchiolitis obliterans

INTRODUCTION: The precise role of the remodeling process and possible therapies for bronchiolitis obliterans remain to be established. OBJETIVE: In the present study, we sought to validate the importance of nasal collagen V tolerance to verify whether bronchovascular axis remodeling could be reverted by this therapeutic approach when compared to steroid treatment. METHODS: Mice were randomly divided into 4 groups: control, bronchiolitis obliterans, collagen V tolerance, and prednisone groups. Morphometry was employed to evaluate bronchovascular axis dimensions, collagen density, and immune cell response. Collagen V nasal tolerance and steroid-treated mice showed significantly lower values of terminal bronchiole wall thickness and reduction in peribronchovascular cells; bronchioalveolar lymphoid tissue; and CD3+, CD4+, CD8+, and CD20+ lymphocytes. A significant decrease in CD68+ macrophage density was found in prednisone-treated mice. In addition, a strong quantitative relationship was found between collagen V tolerance, and reduction in density of immune cells and collagen. RESULTS: Our results indicate that bronchovascular axis remodeling in bronchiolitis obliterans can be reverted by collagen V nasal tolerance, possibly as the result of T-cell suppression. CONCLUSION: We concluded that the tolerance effects in this model were strongly related to the improvement in bronchovascular remodeling, and these may be an appropriate targets for further prospective studies on nasal collagen V tolerance.

INTRODUÇÃO: A participação precisa do processo de remodelamento e possíveis implicações no tratamento da bronquiolite obliterante ainda não está estabelecida. OBJETIVOS: Estabelecer a importância da tolerância nasal induzida pelo colágeno do tipo V e verificar se o processo de remodelamento do eixo broncovascular pode ser revertido com esta estratégia terapêutica comparada ao efeito do tratamento com esteróides. MATERIAL E MÉTODO: Camundongos foram divididos em quatro grupos: controle, bronquiolite obliterante, tolerância nasal com colágeno do tipo V e prednisona. Morfometria foi realizada para avaliar as dimensões do eixo broncovascular, densidade de colágeno e resposta imunocelular. Camundongos submetidos à tolerância nasal com colágeno do tipo V e tratados com prednisona exibiram significativas reduções da espessura da parede de bronquíolos terminais, da densidade de células inflamatórias ao redor do eixo peribroncovascular e da resposta imunocelular às custas de linfócitos CD3, CD4, CD8 e CD20. Houve também significativa redução da densidade de macrófagos CD68 nos camundongos tratados com prednisona. Adicionalmente, houve uma forte associação entre tolerância nasal induzida pelo colágeno do tipo V, resposta imunocelular e redução do conteúdo de colágeno peribroncovascular. RESULTADOS: O remodelamento do eixo broncovascular na bronquiolite obliterante pode ser revertido pela indução de tolerância nasal com o colágeno do tipo V, possivelmente como resultado de supressão de linfócitos T. CONCLUSÃO: Os efeitos da tolerância nasal no presente modelo estiveram fortemente relacionados à melhora no remodelamento do eixo broncovascular, despontando como um alvo promissor para estudos prospectivos.