A biomimetic reverse thermal gel for optic nerve regeneration

描述（由申请人提供）：估计有220万美国人患有青光眼和青光眼相关视神经病变，占美国所有失明病例的9%至12%，并且承认10%接受适当药物治疗的患者继续经历视力下降，显然需要一种替代治疗策略。目前的治疗模式主要集中在降低眼内压（IOP）的药物方法上，尽管有大量证据表明IOP不是青光眼病理生理的唯一致病因素。最近的研究采取了更直接的方法，将视网膜神经节细胞（RGC）死亡导致视神经损伤作为保护视力或逆转视力丧失的一种手段。虽然有些方法是纯药理学的，但在更广泛的神经再生领域的经验告诉我们，基于支架的方法可能是最有前途的策略。我们最近开发了一种聚合物注射生物材料，由于其反向热胶凝特性，它很好地服务于这种应用。这些性质允许它在两者之间迅速而可逆地过渡

DESCRIPTION (provided by applicant): With an estimated 2.2 million Americans with glaucoma and glaucoma-related optic neuropathies accounting for 9 to 12% of all cases of blindness in the U.S., and the acknowledgement that 10% of patients that receive proper medical treatment continue to experience vision loss, there is a clear need for an alternative treatment strategy. The current treatment paradigm is focused on pharmacological approaches to lowering intraocular pressure (IOP), despite myriad evidence indicating IOP is not the only causative factor in the pathophysiology of glaucoma. Recent work has taken a more direct approach in which the retinal ganglion cell (RGC) death causing damage to the optic nerve is targeted as a means to preserve vision or reverse vision loss. While some approaches are purely pharmacological, experience in the wider field of neural regeneration has taught us that a scaffold-based approach may be the most promising strategy. We have recently developed a polymeric injectable biomaterial that serves itself well to this application owing to its reverse thermal gelling properties. These properties allow it too rapidly and reversibly transition between a liquid at room temperature and a solid at body temperature, permitting injection through a small gauge needle or cannula directly at the target site and then formation of a cohesive solid polymer network upon reaching body temperature. This approach has many advantages over other scaffold-based approaches including minimally-invasive deployment, in situ conformation to the injury site and tunable physical properties to mimic the host environment. In addition, this system can be readily functionalized with function-mimicking biomolecules to enhance RGC axon regeneration. By functionally tethering these biomolecules directly to our novel injectable biomaterial, we improve both the targeting and the time-scale of their influence at the injury site Towards developing a system that can maximize these advantages, we have constructed this application around two specific aims: 1) design and characterize an appropriate functionalized, biomimetic injectable biomaterial with favorable reverse thermal gelling behavior and physiochemical properties suited to mimic the host environment for optic nerve regeneration; and 2) demonstrate that the functionalized version of this reverse thermal gel (RTG) substantially enhances RGC axon regeneration in vitro and in in vivo optic nerve crush models. We hypothesize that well-controlled incorporation of biomolecules into a temperature responsive polymeric material will lead to a novel and biomimetic injectable biomaterial that conforms in situ to the injury site and mimics the host environment to maximize RGC axon regeneration.