Amniotic Membrane versus Pericardium in Reducing Glaucoma Drainage Tube Exposure

描述（由申请人提供）： 青光眼引流装置（GDD）已广泛用于治疗高危难治性青光眼。为了避免管暴露，这可能会导致严重的眼部感染，植入的GDD管必须覆盖一个补丁移植传统上由供体巩膜或心包。然而，这些补片移植物仍然具有进行性变薄和糜烂的高发生率，我们推测这是由于周围宿主结膜基质缺乏细胞浸润以及这些补片移植物与宿主组织的整合不良而导致的并发症。我们进一步推测，由Bio-Tissue，Inc.生产的较厚的冷冻保存羊膜（AM），TissueTech，Inc.的全资子公司，可以提供更好的抗张强度，适合于构造支撑，并且具有促进周围宿主结膜基质的细胞浸润的生物活性，从而减少进行性同种异体补片移植物变薄/侵蚀。 通过SBIR I期资助（R43 EY 19785），我们评价了较厚AM作为初次植入期间覆盖GDD管的替代补片移植物。我们使用眼前节光学相干断层扫描（OCT）进一步监测宿主细胞相互作用。我们已经成功实现了上述研究的拟定目标，证明了AM在初次GDD手术中覆盖管的短期稳定性/有效性（I期-目标1），并证实了在GDD管上移植后使用OCT区分宿主细胞浸润到AM中的可行性（I期-目标2）。 在该II期申请中，我们计划进行一项前瞻性对照研究，以比较较厚AM（AmnioGuard”，Bio-Tissue，Inc，迈阿密，佛罗里达州）与心包（Tutoplast（R），IOP Inc，科斯塔梅萨，加利福尼亚州）在固定GDD管和减少高危青光眼患者的管暴露和移植物变薄方面的长期安全性和有效性。我们还将研究可能导致GDD管暴露的风险因素。这项II期研究的完成将使AM成为现有补片移植物的有效替代品，以减少管暴露并提高GDD植入的成功率，同时提供更好的美学外观并允许高危青光眼患者的管可视化。这也将使公司能够将其市场空间从眼表扩展到青光眼疾病。我们推测，这种移植物也可能有其他临床应用以外的覆盖GDD管。

DESCRIPTION (provided by applicant): Glaucoma drainage devices (GDDs) have widely been used in the treatment of high-risk refractory glaucoma. To avoid tube exposure, which may lead to serious eye infection, the implanted GDD tube must be covered by a patch graft traditionally made of either donor sclera or pericardium. However, these patch grafts still carry a high rate of progressive thinning and erosion, a complication that we speculate results from the lack of cellular infiltration from the surrounding host conjunctival stroma and poor integration of these patch grafts to the host tissue. We further speculate that a thicker version of cryopreserved amniotic membrane (AM), manufactured by Bio-Tissue, Inc., a 100%-owned subsidiary of TissueTech, Inc., could offer better tensile strength, be suitable for tectonic support, and have biological activities to promote cellular infiltration by the surrounding host conjunctival stroma, thus reducing progressive allogeneic patch graft thinning/erosion. Through SBIR Phase I grant support (R43 EY19785), we have evaluated the thicker AM as an alternative patch graft for covering the GDD tube during the primary implantation. We further monitored the host cell interaction using anterior segment optical coherence tomography (OCT). We have successfully accomplished the proposed aims of the above studies which demonstrated the short-term stability/efficacy of AM in covering the tube in primary GDD surgery (Phase I- Aim 1), and confirmed the feasibility of using OCT to distinguish host cell infiltration into the AM after transplantation over the GDD tube (Phase I- Aim 2). In this Phase II application, we propose to conduct a prospective, controlled study to compare the long-term safety and efficacy of the thicker AM (AmnioGuard", Bio-Tissue, Inc, Miami, FL) to the pericardium (Tutoplast(R), IOP Inc, Costa Mesa, CA) in securing the GDD tube and reducing tube exposure and graft thinning in patients with high risk glaucoma. We will also study the risk factors that may contribute to GDD tube exposure. Accomplishment of this Phase II study will position AM as an effective alternative to the existing patch grafts to reduce tube exposure and enhance the success of GDD implantation while providing a better aesthetic appearance and allowing visualization of the tube in patients with high risk glaucoma. This will also allow the Company to expand its market space from ocular surface to glaucoma diseases. We speculate that such a graft might also have other clinical applications outside of covering GDD tubes.