Habroosh Fatima, Filippini Perla, Al Saadi Ahmed, Soliman Shady, Yildiz Burcin Kepez, Sahay Prity, Said Dalia G, Dua Harminder S
Academic Ophthalmology, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, United Kingdom.
Department of Ophthalmology, Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates.
Front Med (Lausanne). 2025 Aug 5;12:1612452. doi: 10.3389/fmed.2025.1612452. eCollection 2025.
The pre-Descemet layer (Dua's layer) (PDL/DL) and the Descemet membrane (DM) have the highest expression of elastin in normal corneas. Reduced expression of elastin occurs in the corneal stroma of patients with keratoconus (KC). This study aimed to examine the expression of elastin and that of other extracellular matrix (ECM) components, and proteoglycan proteins in the PDL/DL and DM in advanced KC.
Corneal tissue obtained from four subjects with KC who underwent penetrating keratoplasty was compared with tissue from four normal corneas. The tissues were sectioned and analyzed with specific markers for extracellular matrix proteins and proteoglycans-namely, elastin, collagens I, IV, and VI, fibulin-2, and decorin-using immunohistochemical analysis. Fluorescence intensity was measured using ImageJ software and compared to controls.
The expression of elastin was significantly reduced in the PDL/DL and DM in KC cases compared to controls. Concurrently, an increased expression of elastin was noted anteriorly in the subepithelial region. Expression of collagen IV, collagen VI, and decorin was reduced in the PDL/DL and DM, whereas expression of collagen I and fibulin-2 was unaltered in KC cases compared to controls.
The significant reduction of elastin in the PDL/DL and DM in cases of advanced keratoconus with acute corneal hydrops (ACH) may play a crucial role in the pathology of KC and the subsequent onset of ACH. Furthermore, elastin is considered to be pivotal in the disease progression, as keratoconus typically starts with a posterior elevation affecting these two layers.
前弹力层（杜阿层）（PDL/DL）和后弹力层（DM）在正常角膜中弹性蛋白表达最高。圆锥角膜（KC）患者角膜基质中弹性蛋白表达降低。本研究旨在检测晚期KC患者PDL/DL和DM中弹性蛋白以及其他细胞外基质（ECM）成分和蛋白聚糖蛋白的表达。
将4例接受穿透性角膜移植术的KC患者的角膜组织与4例正常角膜组织进行比较。将组织切片，并用细胞外基质蛋白和蛋白聚糖的特异性标志物，即弹性蛋白、I型、IV型和VI型胶原蛋白、纤维连接蛋白-2和核心蛋白聚糖，进行免疫组织化学分析。使用ImageJ软件测量荧光强度并与对照组进行比较。
与对照组相比，KC患者PDL/DL和DM中弹性蛋白的表达显著降低。同时，上皮下区域前部弹性蛋白表达增加。与对照组相比，KC患者PDL/DL和DM中IV型胶原蛋白、VI型胶原蛋白和核心蛋白聚糖的表达降低，而I型胶原蛋白和纤维连接蛋白-2的表达未改变。
晚期圆锥角膜合并急性角膜水肿（ACH）患者PDL/DL和DM中弹性蛋白的显著减少可能在KC的病理过程及随后ACH的发生中起关键作用。此外，弹性蛋白被认为在疾病进展中起关键作用，因为圆锥角膜通常始于影响这两层的后凸。
