Boswell C A, Noecker R J, Mac M, Snyder R W, Williams S K
Department of Surgery, Section of Surgical Research, Arizona Health Sciences Center, Tucson, Arizona 85724, USA.
J Biomed Mater Res. 1999;48(5):591-5. doi: 10.1002/(sici)1097-4636(1999)48:5<591::aid-jbm1>3.0.co;2-9.
Aqueous drainage devices for the treatment of glaucoma are subject to the same limitations as most polymeric implants, namely a healing response comprised of chronic inflammation and fibrosis. The most widely used devices are currently made of silicone or polypropylene, materials that exhibit biocompatibility difficulties when they are implanted on the sclera underneath the conjunctiva of the eye. Decreased outflow of aqueous fluid to the conjunctival space caused by the development of a fibrous capsule around the device accounts for at least 20% of aqueous shunts failures. Clearly, the need exists to improve the healing response to aqueous drainage devices, and one approach is to develop new polymers or polymer modifications. Improved devices would elicit a limited fibrotic response while increasing neovascularization around the implant. Previous studies have indicated that denucleation markedly improves the healing characteristics and biocompatibility of expanded polytetrafluoroethylene (ePTFE). We reasoned that altering the design of drainage devices to allow the use of denucleated ePTFE in vivo might minimize fibrosis, thereby improving shunt function. We found that after 8 weeks in vivo, experimental shunt function was equivalent to the Baerveldt shunt, while there was less scarring with increased neovascularizatin. These findings suggest that ePTFE has potential as an improved, long-term alternative material for use in constructing glaucoma shunts.
用于治疗青光眼的房水引流装置与大多数聚合物植入物存在相同的局限性，即由慢性炎症和纤维化组成的愈合反应。目前使用最广泛的装置由硅酮或聚丙烯制成，当这些材料植入眼结膜下方的巩膜上时，会出现生物相容性问题。装置周围纤维囊的形成导致房水向结膜间隙的流出减少，这至少占房水分流失败的20%。显然，需要改善对房水引流装置的愈合反应，一种方法是开发新的聚合物或对聚合物进行改性。改进后的装置在增加植入物周围新生血管形成的同时，会引发有限的纤维化反应。先前的研究表明，去核显著改善了膨体聚四氟乙烯（ePTFE）的愈合特性和生物相容性。我们推断，改变引流装置的设计以允许在体内使用去核的ePTFE可能会使纤维化最小化，从而改善分流功能。我们发现，在体内8周后，实验性分流功能与Baerveldt分流相当，同时瘢痕形成较少，新生血管形成增加。这些发现表明，ePTFE有潜力作为一种改良的长期替代材料用于构建青光眼分流装置。
