ELASTIN AND COLLAGEN REMODELING IN EMPHYSEMA - A SCANNING ELECTRON-MICROSCOPY STUDY

The relationship between elastin degradation and emphysema is wed know n. Recent evidence suggests that a complex process of pulmonary remode ling occurs within the emphysematous lung, The aim of this study was t o assess the extent of extracellular matrix remodeling in emphysema by ultrastructural examination of elastin and collagen templates in an a nimal model of emphysema and in human emphysematous lungs, Emphysema w as induced in mts by the intratracheal administration of porcine pancr eatic elastase, Human lung samples were obtained at surgical resection for lung carcinoma, Emphysema was confirmed morphometrically and quan titated using the mean linear intercept, Matching sections were treate d with sodium hydroxide and formic acid to expose collagen and elastin templates, respectively, Scanning electron microscopy with stereo-pai r imaging allowed three-dimensional visualization of the exposed templ ates, In emphysematous lungs from both sources, sheets of elastin were disrupted and perforated with multiple fenestrations. In elastase-ind uced emphysema, this disintegration was accompanied by a marked increa se is thickness of collagen fibrils, which contrasted with the fine fi brillar network of control lungs, Similarly, a pattern of thickened fi brils and disorganized deposition of collagen was observed in human lu ngs. In conclusion, these findings support the novel concept of increa sed collagen deposition and aberrant collagen remodeling in the pathog enesis of emphysema.