Bicket Amanda Kiely, Szeto Julia, Roeber Peter, Towler Jeff, Troutman Mitch, Craven E Randy, Khatana Anup, Ahmed Ike, Quigley Harry, Ramulu Pradeep, Pitha Ian F
Wilmer Eye Institute, Johns Hopkins University School of Medicine Baltimore Maryland USA.
W.L. Gore & Associates Newark Delaware USA.
Bioeng Transl Med. 2020 Aug 22;6(1):e10179. doi: 10.1002/btm2.10179. eCollection 2021 Jan.
The purpose of these studies was to evaluate clinical, functional, and histopathological features of glaucoma drainage implants (GDIs) fabricated from novel, custom-tailored expanded polytetrafluoroethylene (ePTFE). Implants of matching footprints were fabricated from silicone (Control) and novel, bilayered ePTFE. ePTFE implants included: (a) one that inflated with aqueous humor (AH) (High), (b) one that inflated with a lower profile (Low), (c) an uninflated implant not connected to the anterior chamber (Flat), and (d) one filled with material that did not allow AH flow (Filled). All implants were placed in adult New Zealand White rabbits and followed over 1-3 months with clinical exams and intraocular pressure. The permeability of tissue capsules surrounding GDIs was assessed using constant-flow perfusion with fluoresceinated saline at physiologic flow rates. After sacrifice, quantitative histopathological measures of capsule thickness were compared among devices, along with qualitative assessment of cellular infiltration and inflammation. Capsular thickness was significantly reduced in blebs over ePTFE (61.4 ± 53 μm) versus silicone implants (193.6 ± 53 μm, = .0086). AH exposure did not significantly alter capsular thickness, as there was no significant difference between High and Filled (50.9 ± 29, = .34) implants. Capsules around ePTFE implants demonstrated permeability with steady-state pressure: flow relationships at physiologic flow rates and rapid pressure decay with flow cessation, while pressure in control blebs increased even at low flow rates and showed little decay. Perfused fluorescein dye appeared beyond the plate border only in ePTFE implants. ePTFE implants are associated with thinner, more permeable capsules compared to silicone implants simulating presently used devices.
这些研究的目的是评估由新型定制膨体聚四氟乙烯（ePTFE）制成的青光眼引流植入物（GDI）的临床、功能和组织病理学特征。制作了尺寸匹配的硅胶植入物（对照）和新型双层ePTFE植入物。ePTFE植入物包括：（a）一种可被房水（AH）充盈的植入物（高），（b）一种以较低外形充盈的植入物（低），（c）一种未与前房相连的未充盈植入物（平），以及（d）一种填充有不允许房水流动材料的植入物（填充）。将所有植入物植入成年新西兰白兔体内，并通过临床检查和眼压监测进行1至3个月的随访。使用生理流速的荧光素标记盐水恒流灌注来评估GDI周围组织囊的通透性。处死动物后，比较各装置之间囊厚度的定量组织病理学测量结果，以及细胞浸润和炎症的定性评估。与硅胶植入物（193.6±53μm，P = 0.0086）相比，ePTFE植入物上方的泡内囊厚度显著降低（61.4±53μm）。房水暴露并未显著改变囊厚度，因为高充盈植入物和填充植入物之间没有显著差异（50.9±29，P = 0.34）。ePTFE植入物周围的囊在生理流速下呈现出稳态压力：流量关系以及流量停止时压力快速衰减，而对照泡内的压力即使在低流速下也会升高且几乎没有衰减。灌注的荧光素染料仅在ePTFE植入物中出现在板边界之外。与模拟当前使用装置的硅胶植入物相比，ePTFE植入物与更薄、更具通透性的囊相关。
