Ylikärppä Ritva, Eklund Lauri, Sormunen Raija, Kontiola Antti I, Utriainen Aino, Määttä Marko, Fukai Naomi, Olsen Björn R, Pihlajaniemi Taina
Collagen Research Unit, Biocenter Oulu and Department of Medical Biochemistry and Molecular Biology, University of Oulu, Finland.
FASEB J. 2003 Dec;17(15):2257-9. doi: 10.1096/fj.02-1001fje. Epub 2003 Oct 2.
Mice lacking type XVIII collagen have defects in the posterior part of the eye, including delayed regression of the hyaloid vasculature and poor outgrowth of the retinal vessels. We report here that these mice also have a fragile iris and develop atrophy of the ciliary body. The irises of Col18a1-/- mice can be seen to adhere to the lens and cornea. After the pupils begin to function, the double layer of epithelial cells separates at the apical cell contacts, leading to defoliation of its posterior pigment epithelial cell layer, and extracellular material begins to accumulate in the basement membrane zones of the iris. In contrast to the iris epithelia, where no clear signs of cellular atrophy were detected, the lack of type XVIII collagen resulted in atrophy of the pigmented epithelial cells of the ciliary body, and there were also ultrastructural abnormalities in the basement membrane zones. These changes did not lead to chronically elevated intraocular pressures, however. Our results indicate that type XVIII collagen is needed for the integrity of the epithelial basement membranes of the iris and the ciliary body and that its gene should therefore be taken into account as a new potential cause of anterior segment disorders in the eye.
缺乏 XVIII 型胶原蛋白的小鼠眼睛后部存在缺陷，包括玻璃体血管系统的消退延迟和视网膜血管的生长不良。我们在此报告，这些小鼠还具有脆弱的虹膜并出现睫状体萎缩。可以看到 Col18a1-/- 小鼠的虹膜与晶状体和角膜粘连。瞳孔开始发挥功能后，双层上皮细胞在顶端细胞连接处分离，导致其后部色素上皮细胞层脱叶，细胞外物质开始在虹膜的基底膜区域积聚。与未检测到明显细胞萎缩迹象的虹膜上皮不同，缺乏 XVIII 型胶原蛋白导致睫状体色素上皮细胞萎缩，基底膜区域也存在超微结构异常。然而，这些变化并未导致眼压长期升高。我们的结果表明， XVIII 型胶原蛋白是虹膜和睫状体上皮基底膜完整性所必需的，因此其基因应被视为眼部前段疾病的一个新的潜在病因。
