Idiopathic epiretinal membranes are sheets of tissue that develop in the vitreoretinal interface. They are formed by cells and extracellular matrix, and they are considered the expression of a fibrotic disorder of the eye. Confocal and immunoelectron microscopy of the extracellular matrix of excised membranes, revealed high contents of type IV collagen. It was distributed within epiretinal membranes in basement membrane-like structures associated with cells and in interstitial deposits. In both cases, type IV collagen was always associated with type I collagen. Col IV was also coupled with Col VI and laminin. At high magnification, type IV collagen immunolabelling was associated with interstitial deposits and showed a reticular appearance due to the intersection of beaded microfilaments. The microfilaments are about 12 nm in diameter with interbead distance of 30-40 nm. Cells of the epiretinal membranes showed intracellular lysosome-like bodies heavily labeled for type IV collagen suggesting an active role in membrane remodeling. Hence, type IV collagen is not necessarily always associated with basement membranes; the molecular interactions that it may develop when not incorporated in basement membranes are still unknown. It is conceivable, however, that they might have implications in the progression of epiretinal membranes and other fibrotic disorders.

中文翻译：

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视网膜前膜中IV型胶原沉积的特殊模式。

特发性视网膜前膜是在玻璃体视网膜界面发育的组织薄片。它们由细胞和细胞外基质形成，被认为是眼睛纤维化疾病的表达。共聚焦和免疫电子显微镜观察细胞膜的细胞外基质，发现IV型胶原蛋白含量高。它分布在与细胞相关的基底膜样结构和间质沉积物中的视网膜前膜内。在这两种情况下，IV型胶原始终与I型胶原相关。Col IV还与Col VI和层粘连蛋白结合。在高放大倍率下，IV型胶原蛋白免疫标记与间质沉积有关，由于珠状微丝的相交而显示出网状外观。微丝的直径为约12nm，珠间距离为30-40nm。前视网膜膜细胞显示出细胞内溶酶体样小体，大量标记了IV型胶原，表明在膜重塑中起积极作用。因此，IV型胶原蛋白不一定总是与基底膜相关。当它不掺入基膜中时，可能发生的分子相互作用仍是未知的。但是，可以想象它们可能对视网膜前膜和其他纤维变性疾病的进展有影响。当它不掺入基膜中时，可能发生的分子相互作用仍是未知的。但是，可以想象它们可能对视网膜前膜和其他纤维变性疾病的进展有影响。当它不掺入基膜中时，可能发生的分子相互作用仍是未知的。但是，可以想象它们可能对视网膜前膜和其他纤维变性疾病的进展有影响。