Remodelamento da matriz extracelular em degeneração experimental do disco intervertebral / Extracellular matrix remodeling in experimental intervertebral disc degeneration

Objetivo: Avaliar a remodelação da matriz extracelular na degeneração do disco intervertebral através do modelo experimental degeneração do disco intervertebral. Métodos: o modelo de indução da degeneração discal, utilizando agulha 20G e rotação de 360º, foi aplicado por 30 segundos entre a sexta/sétima e oitava / nona vértebras coccígeas de ratos machos da linhagem Wistar. O nível intermediário, entre a sétima e oitava vértebras, foi tomado como controle, não sendo submetido à punção. A distribuição de constituintes da matriz extracelular envolvidos com mecanismos de remodelamento e inflamação, como proteoglicanos (agrecam, decorim, biglicam), fatores de crescimento (TGFβ), isoformas de heparanase (HPSE1, HPSE2), metaloprotease-9 (MMP9) e interleucinas (IL-6, IL-10) foram avaliadas no período pós-lesão (15 e 30 dias) e no grupo controle (discos coletados imediatamente após a punção, dia zero). No 15 o dia, fase aguda da doença, notou-se redução da expressão dos constituintes da matriz extracelular, porém não houve diferenças na expressão de interleucinas. Aos 30 dias, as moléculas seguiram um padrão de expressão muito similar ao grupo controle (não acometido por degeneração discal). Resultados: os resultados mostram que na fase aguda ocorrem alterações significativas na matriz extracelular e, na fase tardia, o disco intervertebral retorna a um perfil semelhante ao tecido não acometido por degeneração, provavelmente devido a um intenso processo de remodelamento da matriz extracelular que é capaz de regenerar o tecido lesionado. Conclusão: o modelo experimental utilizado demonstrou a ocorrência de alterações significativas da matriz extracelular durante o período analisado após a indução da degeneração do disco intervertebral. Trabalho experimental.

Objective: To evaluate the remodeling of the extracellular matrix in intervertebral disc degeneration through the experimental model of intervertebral disc degeneration. Methods: The model of disk degeneration induction, using needle 20G and 360º rotation, was applied for 30 seconds between the 6th/7th , and 8th/9th coccygeal vertebrae of Wistar rats. The intermediary level, between th e 7th and 8th vertebrae, was taken as control, not being subjected puncture. The distribution of the extracellular matrix components involved in the remodeling and inflammation process, such as proteoglycans (aggrecan, decorin, biglycan), growth factors (TGFβ), heparanase isoforms (HPSE1, HPSE2), metaloprotesasis-9 (MMP9) and interleukins (IL-6, IL-10) was analyzed during the pos-injury period (15 to 30 days) and in the control group (discs collected immediately after the puncture, day zero). On the 15th day, acute phase of the disease, a reduced expression of extracellular matrix components had been observed, whilst there were no differences in the interleukins expression. At 30 days, the molecules followed a very similar pattern of expression in the control group (not affected by disc degeneration). Results: the results show that during the acute phase significant alterations in the extracellular matrix components occur and in the late phase intervertebral disc returns to a profile similar to noninvolved tissue, probably due to extensive remodeling process of the extracellular matrix that is capable of regenerating the damaged tissue. Conclusion: the experimental model used demonstrated the occurrence of significant changes in the extracellular matrix during the period analyzed after induction of intervertebral disc degeneration. Laboratory investigation.

Imunofenotipagem e remodelamento da matriz extracelular na sarcoidose pulmonar e extrapulmonar / Immunophenotyping and extracellular matrix remodeling in pulmonary and extrapulmonary sarcoidosis

OBJETIVO: Investigar o significado de marcadores de imunidade celular e de componentes elásticos/colágeno da matriz extracelular em estruturas granulomatosas em biópsias de pacientes com sarcoidose pulmonar ou extrapulmonar. MÉTODOS: Determinações qualitativas e quantitativas de células inflamatórias, de fibras de colágeno e de fibras elásticas em estruturas granulomatosas em biópsias cirúrgicas de 40 pacientes com sarcoidose pulmonar e extrapulmonar foram realizadas por histomorfometria, imuno-histoquímica, e técnicas de coloração com picrosirius e resorcina-fucsina de Weigert. RESULTADOS: A densidade de linfócitos, macrófagos e neutrófilos nas biópsias extrapulmonares foi significativamente maior do que nas biópsias pulmonares. Os granulomas pulmonares apresentaram uma quantidade significativamente maior de fibras de colágeno e menor densidade de fibras elásticas que os granulomas extrapulmonares. A quantidade de macrófagos nos granulomas pulmonares correlacionou-se com CVF (p < 0,05), ao passo que as quantidades de linfócitos CD3+, CD4+ e CD8+ correlacionaram-se com a relação VEF1/CVF e com CV. Houve correlações negativas entre CPT e contagem de células CD1a+ (p < 0,05) e entre DLCO e densidade de fibras colágenas/elásticas (r = -0,90; p = 0,04). CONCLUSÕES: A imunofenotipagem e o remodelamento apresentaram características diferentes nas biópsias dos pacientes com sarcoidose pulmonar e extrapulmonar. Essas diferenças correlacionaram-se com os dados clínicos e espirométricos dos pacientes, sugerindo que há duas vias envolvidas no mecanismo de depuração de antígenos, que foi mais eficaz nos pulmões e linfonodos.

OBJECTIVE: To investigate the significance of cellular immune markers, as well as that of collagen and elastic components of the extracellular matrix, within granulomatous structures in biopsies of patients with pulmonary or extrapulmonary sarcoidosis. METHODS: We carried out qualitative and quantitative evaluations of inflammatory cells, collagen fibers, and elastic fibers in granulomatous structures in surgical biopsies of 40 patients with pulmonary and extrapulmonary sarcoidosis using histomorphometry, immunohistochemistry, picrosirius red staining, and Weigert's resorcin-fuchsin staining. RESULTS: The extrapulmonary tissue biopsies presented significantly higher densities of lymphocytes, macrophages, and neutrophils than did the lung tissue biopsies. Pulmonary granulomas showed a significantly higher number of collagen fibers and a lower density of elastic fibers than did extrapulmonary granulomas. The amount of macrophages in the lung samples correlated with FVC (p < 0.05), whereas the amount of CD3+, CD4+, and CD8+ lymphocytes correlated with the FEV1/FVC ratio and VC. There were inverse correlations between TLC and the CD1a+ cell count (p < 0.05), as well as between DLCO and collagen/elastic fiber density (r = -0.90; p = 0.04). CONCLUSIONS: Immunophenotyping and remodeling both showed differences between pulmonary and extrapulmonary sarcoidosis in terms of the characteristics of the biopsy samples. These differences correlated with the clinical and spirometric data obtained for the patients, suggesting that two different pathways are involved in the mechanism of antigen clearance, which was more effective in the lungs and lymph nodes.

Intrinsic and extrinsic circuits controling the thymic microenvironment

The thymic microenvironment plays a key role in the general process of intrathymic T cell differentiation, that ultimately yields the vast majority of the T cell repertoire. This nonlymphoid compartment is mostly composed of thymic epithelial cells (TEC), that together with dendritic cells, macrophages and elements of the extracellular matrix form a tridimensional network in which context thymocyte differentiation occurs. Microenvironmental cells modulate intrathymic T cell diferentiation by means of a variety of secretory products, comprising several cytokines and thymic hormones, as well as cell-cell interactions, including those mediated by MHC products, adhesion molecules and extracellular matrix ligands and receptors. When studying the physiology of the thymic microenvironment one should take into account the existence of intrinsic and extrinsic circuits controlling it. For example, we showed that interferon-gamma (IFN-gamma), a thymocyte-derived cytokine, is able to pleiotropically modulate both epithelial and dendritic cells of the thymus. Besides enhancing the expression of MHC class two molecules on these cell types, IFN-gamma regulates, in a dose-dependent biphasic manner, the expression of extracellular matrix ligands and receptors that implies a corresponding modulation on the ability of thymocytes to adhere onto IFN-gamma-treated TEC cultures. In addition, extrinsic endogenous circuits appear to continuously influence the thymic microenvironment. We evidenced that steroid, thyroid and pituitary hormones can modulate several aspects of TEC physiology including thymic hormone secretion, cytokeratin expression, cell growth as well as expression of extracellular matrix ligands and receptors. Latter effects directly intervene, at least as assessed by in vitro models, in TEC/thymocyte interactions. Other endogenous situations such as aging and autoimmunity also influence the thymic microenvironment. For example, in both conditions we showed a decay in thymic hormone secretion, changes in the expression of cortical and medullary cytokeratins, and an increase in extracellular matrix. Furthermore, the thymic microenvironment is modulated by stimuli from the environmental world such as infectious agents. In the Trypanosoma cruzi model, we noticed that both TEC and thymic macrophages are infected in vivo and in vitro...

Autoantibodies as tools for biochemists and cell biologists

In this report we deal with the interesting repertoire of autoantigens and discuss that they represent functional and evolutionary conserved sites in proteins. In addition, we show that the autoantibodies spontaneously generated against these antoantigens can be useful tools in the study of important cellular phenomena.