The extracellular matrix of the lung and its role in edema formation

The extracellular matrix is composed of a three-dimensional fiber mesh filled with different macromolecules such as: collagen (mainly type I and III), elastin, glycosaminoglycans, and proteoglycans. In the lung, the extracellular matrix has several functions which provide: 1) mechanical tensile and compressive strength and elasticity, 2) low mechanical tissue compliance contributing to the maintenance of normal interstitial fluid dynamics, 3) low resistive pathway for an effective gas exchange, d) control of cell behavior by the binding of growth factors, chemokines, cytokines and the interaction with cell-surface receptors, and e) tissue repair and remodeling. Fragmentation and disorganization of extracellular matrix components comprises the protective role of the extracellular matrix, leading to interstitial and eventually severe lung edema. Thus, once conditions of increased microvascular filtration are established, matrix remodeling proceeds fairly rapidly due to the activation of proteases. Conversely, a massive matrix deposition of collagen fiber decreases interstitial compliance and therefore makes the tissue safety factor stronger. As a result, changes in lung extracellular matrix significantly affect edema formation and distribution in the lung.

A matriz extracelular é um aglomerado tridimensional demacromoléculas composta por: fibras colágenas (principalmente, tipos I e III), elastina, glicosaminoglicanos e proteoglicanos. No pulmão, a matriz extracelular tem várias funções, tais como: 1) promover estresse tensil e elasticidade tecidual, 2) contribuir para a manutenção da dinâmica de fluidos no interstício, 3) propiciar efetiva troca gasosa, 4) controlar a função celular através de sua ligação com fatores de crescimento, quimiocinas, citocinas e interação com receptores de superfície, e 5) remodelamento e reparo tecidual. A fragmentação e a desorganização da matriz extracelular pode acarretar edema intersticial e, eventualmente, edema alveolar grave. Logo, quando há aumento da filtração microvascular ocorre rápido remodelamento da matriz por ativação de proteases. Destarte, a deposição de fibras colágenas reduz a complacência intersticial limitando o edema. Em conclusão, modificações na matriz extracelular podem afetar a formação e distribuição do edema no pulmão.

Does internal limiting membrane peeling in macular hole surgery improve reading vision?

PURPOSE: To document the effect of internal limiting membrane (ILM) peeling in macular hole closure and reading vision. METHOD: Fifty-four patients with idiopathic and traumatic macular hole underwent standard vitreous surgery and received either ILM peeling (n=25) or no ILM peeling (n=29). The hole closure, and Snellen acuity (distant and near) were recorded 12 weeks after surgery and statistically analysed. RESULTS: The macular hole closure rate was 96% (24 of 25) and 72.4% (21 of 29) with and without ILM peeling respectively (P = 0.028). Distant vision improvement of two or more lines was recorded in 64% (16 of 25) and 51.7% (15 of 29) eyes (P = 0.417) with and without ILM peeling respectively. Near vision improvement of two or more lines was seen in 68% (17 of 25) and 41.2% (12 of 29) eyes (P = 0.048) with and without ILM peeling respectively. CONCLUSION: ILM peeling in macular hole surgery improves the macular hole closure rate and reading vision.

Extracellular matrix glucoprotein metabolism in patients with systemic lupus erythematosus and rheumatoid arthritis: another evidence for basement membrane involvement

The aim of this study was to investigate laminin metabolism in patients with systemic lupus erythematosus [SLE] and rheumatoid arthritis [RA]. Twenty patients with SLE, 20 RA patients and 20 patients with osteoarthritis [OA] were recruited for the study. Twenty age and sex matched healthy persons served as control for SLE, while another 20 age and sex matched control subjects were recruited to serve as control for RA and OA patients. This study provided evidence for basement membrane involvement in patients with SLE and RA. Serum LPI can be used as a marker differentiating inflammatory versus degenerative arthritis. The effect of cyclophosphamide on serum LPI should be taken in consideration in future studies

Hipofluorescência setorial, näo fisiológica, na degeneraçäo macular relacionada a idade: frequência e hipóteses fisiopatológicas / Non-physiological, sectorial hypofluorescence in age-related macular degeneration: frequency and hypothesis

Entre 100 pacientes com diagnóstico angiográfico de degeneraçäo macular relacionada a idade 23 exibiram sinais hipofluorescentes sugestivos e indiretos de eventual espessamento a nível do epitélio pigmentar e ou estruturas contíguas. Embora näo haja confirmaçäo histo-patológica, estes aspectos podem fazer parte dos fatores envolvidos na gênese deste quadro. A hipofluorescência definida a partir do tempo de trânsito do corante pode vir ou de um déficit perfusional na coriocapilar ou de um bloqueio mecânico ou difusional do corante